Detection and alert of automobile braking event

ABSTRACT

A method and system alert a driver of a driven vehicle about an unsafe traffic condition. The method detects, by one or more of a radar detector, a Light Detection and Ranging (LIDAR) detector, or a camera, a braking event of a nearby vehicle. The method stores, in a storage device, the braking event of the nearby vehicle. The method communicates a signal indicative of the braking event of the nearby vehicle to a brake system of the driven vehicle. The method also alerts the driver, by one or more of a user display alert or an audible alert, of the braking event of the nearby vehicle.

CROSS REFERENCES TO RELATED APPLICATIONS

The present application is a continuation of U.S. patent applicationSer. No. 14/874,471, filed Oct. 5, 2015, now U.S. Pat. No. 9,551,582,which is a continuation of U.S. patent application Ser. No. 14/223,864,filed Mar. 24, 2014, now U.S. Pat. No. 9,151,633, issued Oct. 6, 2015,which is a division of U.S. patent application Ser. No. 11/467,923,filed Aug. 29, 2006, now U.S. Pat. No. 8,373,582, which is acontinuation of U.S. patent application Ser. No. 10/937,044, filed Sep.9, 2004, now U.S. Pat. No. 7,268,700, and which is a continuation ofU.S. patent application Ser. No. 10/899,845 filed Jul. 27, 2004, nowU.S. Pat. No. 7,271,737, and which is a continuation of U.S. patentapplication Ser. No. 10/899,850 filed Jul. 27, 2004, now U.S. Pat. No.7,298,289, which are continuations of application Ser. No. 09/884,542filed Jun. 19, 2001, now U.S. Pat. No. 6,791,472, which is acontinuation of application Ser. No. 09/584,056 filed May 30, 2000, nowU.S. Pat. No. 6,429,812, which is a continuation of patent applicationSer. No. 09/236,184 filed Jan. 25, 1999, now U.S. Pat. No. 6,252,544,which claims benefit of priority from Provisional Patent Application No.60/072,757 filed Jan. 27, 1998, each of which is expressly incorporatedherein by reference.

FIELD OF THE INVENTION

The present invention relates to the field of communications devices,and more particularly to mobile telecommunications devices havingposition detection and event storage memory.

BACKGROUND OF THE INVENTION

A number of devices are known which provide mobile telecommunicationcapabilities. Further, known position detection systems employ the knownGlobal Positioning System (GPS), Global Orbiting Navigational System(GLONASS), Loran, RF triangulation, inertial frame reference andCellular Telephone base site, e.g., time difference of arrival (TDOA) ornearest antenna proximity systems. Known GPS mobile systems includememory to record location, time and event type, and some systems may beintegrated with global information systems, to track path, speed, etc.Known Differential GPS (DGPS) systems include mobile telecommunicationfunctionality to communicate between distant units, typically to allowvery precise relative position measurements, in the presence ofsubstantial absolute position errors, or to calibrate the position of amobile transceiver based on a relative position with respect to a fixedtransceiver having a known location. These systems do not typicallyintercommunicate event information between units. Thus, thecommunications streams relate to position information only. However,known weather balloon transceiver systems, for example, do transmit bothposition and weather information to a base station.

Many electronic location determination systems are available, or havebeen proposed, to provide location information to a user equipped with alocation determination receiver. Ground-based location determinationsystems, such as Loran, Omega, TACAN, Decca, U.S. Airforce JointTactical Information Distribution System (JTIDS Relnav), or U.S. ArmyPosition Location and Reporting System (PLRS), use the intersection ofhyperbolic surfaces to provide location information. A representativeground system is LORAN-C discussed in LORAN-C User Handbook, Departmentof Transportation, U.S. Coast Guard, Commandant Instruction M16562.3,May 1990, which is incorporated by reference herein. LORAN-C provides atypical location accuracy of approximately 400 meters. A limitation of aLORAN-C location determination system is that not all locations in thenorthern hemisphere, and no locations in the southern hemisphere, arecovered by LORAN-C. A second limitation of LORAN-C is that the typicalaccuracy of approximately 400 meters is insufficient for manyapplications. A third limitation of LORAN-C is that weather, localelectronic signal interference, poor crossing angles, closely spacedtime difference hyperbolas, and skywaves (multipath interference)frequently cause the accuracy to be significantly worse than 400 meters.

Other ground-based location determination devices use systems that weredeveloped primarily for communications, such as cellular telephone, FMbroadcast, and AM broadcast. Some cellular telephone systems provideestimates of location, using comparison of signal strengths from threeor more sources. FM broadcast systems having subcarrier signals canprovide estimates of location by measuring the phases of the subcarriersignals. Kelley et al. in U.S. Pat. No. 5,173,710 disclose a system thatallows determination of a location of a vehicle. FM subcarrier signalsare received from three FM radio stations with known locations butunknown relative phases by signal processors at the vehicle as well asat a fixed station having a known location. The fixed station processordetermines the relative phase of the signals transmitted by the three FMradio stations and transmits the relative phase information to thevehicle. The vehicle processor determines its location from the FMsubcarrier signal phases and from the relative phase information itreceives. A limitation of cellular systems and FM subcarrier systems forlocation determination is that they are limited to small regions, withdiameters of the order of 20-50 km.

Satellite-based location determination systems such as GPS and GLONASS,use the intersection of spherical surface areas to provide locationinformation with a typical (selective availability) accuracy of 100meters, anywhere on or near the surface of the earth. These systems mayalso be used to obtain positional accuracies within 1 centimeter. Thesatellite-based location determination systems include satellites havingsignal transmitters to broadcast location information and controlstations on earth to track and control the satellites. Locationdetermination receivers process the signals transmitted from thesatellites and provide location information to the user.

The Global Positioning System (GPS) is part of a satellite navigationsystem developed by the United States Defense Department under itsNAVSTAR satellite program. A fully operational GPS includes up to 24satellites approximately uniformly dispersed around six circular orbitswith four satellites each, the orbits being inclined at an angle of55.degree., relative to the equator, and being separated from each otherby multiples of 60.degree. longitude. The orbits have radii of 26,560kilometers and are approximately circular. The orbits arenon-geosynchronous, with 0.5 sidereal day (11.967 hours) orbital timeintervals, so that the satellites move with time, relative to the Earthbelow. Theoretically, four or more GPS satellites will have line ofsight to most points on the Earth's surface, and line of sight access tothree or more such satellites can be used to determine an observer'sposition anywhere on the Earth's surface, 24 hours per day. Eachsatellite carries a cesium or rubidium atomic clock to provide timinginformation for the signals transmitted by the satellites. Internalclock correction is provided for each satellite clock.

A second configuration for global positioning is GLONASS, placed inorbit by the former Soviet Union and now maintained by the RussianRepublic. GLONASS also uses 24 satellites, distributed approximatelyuniformly in three orbital planes of eight satellites each. Each orbitalplane has a nominal inclination of 64.8.degree. relative to the equator,and the three orbital planes are separated from each other by multiplesof 120.degree. longitude. The GLONASS circular orbits have smallerradii, about 25,510 kilometers, and a satellite period of revolution of8/17 of a sidereal day (11.26 hours). A GLONASS satellite and a GPSsatellite will thus complete 17 and 16 revolutions, respectively, aroundthe Earth every 8 sidereal days. The signal frequencies of both GPS andGLONASS are in L-band (1 to 2 GHz).

Because the signals from the satellites pass through the troposphere foronly a short distance, the accuracy of satellite location determinationsystems such as GPS or GLONASS is largely unaffected by weather or localanomalies. A limitation of GLONASS is that it is not clear that theRussian Republic has the resources to complete and to maintain thesystem for full world wide 24 hour coverage.

The inherent accuracy of the GPS position measured by a commercial GPSreceiver is approximately 20 meters. However, the United StatesGovernment currently intentionally degrades the accuracy of GPS computedpositions for commercial users with Selective Availability, SA. With SA,the GPS position accuracy of a commercial GPS receiver is approximately100 meters. However, higher accuracy is available with the use of secretdecryption codes.

Differential Global Positioning System, DGPS, is a technique forenhancing the accuracy of the GPS position, and of course may be appliedto GLONASS as well. The DGPS comprises the Global Positioning Systemtogether with a GPS reference station receiver situated at a knownposition. DGPS error correction information is derived by taking thedifference between the measurements made by the GPS reference stationand the expected measurement at the known position of the referencestation. DGPS error correction information can be in the form of GPSsatellite pseudorange offsets or GPS position offsets. If GPS positionoffsets are used, the GPS satellites used in the calculation of the GPSposition must be included as part of the DGPS error correctioninformation. A processor in a “differential-ready” GPS receiver appliesthe DGPS error correction information to enhance the GPS position to anaccuracy in the range of 10 meters to a less than one meter.

Two types of DGPS exist, postprocessed and realtime. In postprocessedsystems, the DGPS error correction information and a user's GPS positioninformation are processed after the user has completed his dataacquisition. In realtime systems, the DGPS error correction informationis transmitted to the GPS user in a DGPS telemetry stream, e.g., a radiowave signal, and processed by a differential-ready GPS receiver as theapplication progresses. Realtime processing is desirable for manyapplications because the enhanced accuracy of DGPS is available to theGPS user while in the field. Realtime broadcast of DGPS error correctioninformation is available from many sources, both public and private,including Coast Guard RDF beacon and commercially operated FM broadcastsubcarriers. A DGPS radio wave receiver is required to receive the DGPSradio wave signal containing the DGPS error correction information, andpass the DGPS error corrections to the differential-ready GPS receiver.

Many applications of GPS including mineral surveying, mapping, addingattributes or features to maps, finding sites on a map, vehiclenavigation, airplane navigation, marine navigation, field assetmanagement, geographical information systems, and others require theenhanced accuracy that is available with DGPS. For instance, a 20 to 100meter error could lead to unintentional trespassing, make the return toan underground asset difficult, or put a user on the wrong block whilewalking or driving in a city. These applications require a computer tostore and process data, retain databases, perform calculations, displayinformation to a user, and take input from a user entry. For instance,the user may need to store a map database, display a map, add attributesto features on the map, and store these attributes for geographicalinformation. The user may also need to store and display locations orcalculate range and bearing to another location.

GPS is typically used by many professionals engaged in navigation andsurveying fields such as marine navigation, aircraft piloting,seismology, boundary surveying, and other applications where accuratelocation is required or where the cost of GPS is small compared to thecost of a mistake in determining location. Some mobile professionals inthe utilities, insurance, ranching, prospecting, ambulance driving,trucking, delivery, police, fire, real estate, forestry, and othermobile applications use GPS to save time in their work. GPS is also usedfor personal travel such as hiking, biking, horseback riding, yachting,fishing, driving in personal cars, and other travel activities. Toenhance the usefulness of GPS a number of sources have integrated mapsinto the output, or provide a global information system (GIS) to processthe GPS output. Thus, it is known to sort and display proximate mapfeatures and/or attributes in the same coordinate system as the positioninformation.

As disclosed in U.S. Pat. No. 5,528,248, incorporated herein byreference, a satellite location determination system using GlobalPositioning System (GPS) satellite signal transmitters receives a spreadspectrum L1 carrier signal having a frequency=1575.42 MHz. The L1 signalfrom each satellite signal transmitter is binary phase shift key (BPSK)modulated by a Coarse/Acquisition (C/A) pseudo-random noise (PRN) codehaving a clock or chip rate of f0=1.023 MHz. Location information istransmitted at a rate of 50 baud. The PRN codes allow use of a pluralityof GPS satellite signal transmitters for determining an observer'sposition and for providing location information. A signal transmitted bya particular GPS satellite is selected by generating and correlating thePRN code for that particular satellite signal transmitter with a GPSsignal received from that satellite. All C/A PRN codes used for GPSsatellite signals are known and are stored and/or generated in a GPSreceiver. A bit stream from the GPS satellite signal transmitterincludes an ephemeris location of the GPS satellite signal transmitter,an almanac location for all GPS satellites, and correction parametersfor ionospheric signal propagation delay, and clock time of the GPSsatellite signal transmitter. Accepted methods for generating theC/A-code are set forth in the document GPS Interface Control DocumentICD-GPS-200, published by Rockwell International Corporation, SatelliteSystems Division, Revision A, 26 Sep. 1984, which is incorporated byreference herein.

Energy on a single carrier frequency from all of the satellites istransduced by the receiver at a point close to Earth. The satellitesfrom which the energy originated are identified by modulating thecarrier transmitted from each satellite with pseudorandom type signals.In one mode, referred to as the coarse/acquisition (C/A) mode, thepseudorandom signal is a gold code sequence having a chip rate of 1.023MHz; there are 1,023 chips in each gold code sequence, such that thesequence is repeated once every millisecond (the chipping rate of apseudorandom sequence is the rate at which the individual pulses in thesequence are derived and therefore is equal to the code repetition ratedivided by the number of members in the code; one pulse of the noisecode is referred to as a chip).

The 1.023 MHz gold code sequence chip rate enables the position of thereceiver responsive to the signals transmitted from four of thesatellites to be determined to an accuracy of approximately 60 to 300meters.

There is a second mode, referred to as the precise or protected (P)mode, wherein pseudorandom codes with chip rates of 10.23 MHz aretransmitted with sequences that are extremely long, so that thesequences repeat no more than once per week. In the P mode, the positionof the receiver can be determined to an accuracy of approximately 16 to30 meters. However, the P mode requires Government classifiedinformation about how the receiver is programmed and is intended for useonly by authorized receivers. Hence, civilian and/or military receiversthat are apt to be obtained by unauthorized users are not responsive tothe P mode.

To enable the receivers to separate the C/A signals received from thedifferent satellites, the receiver includes a plurality of differentlocally derived gold code sources, each of which corresponds with thegold code sequence transmitted from one of the satellites in the fieldof the receiver. The locally derived and the transmitted gold codesequences are cross correlated with each other over one millisecond,gold code sequence intervals. The phase of the locally derived gold codesequences vary on a chip-by-chip basis, and then within a chip, untilthe maximum cross correlation function is obtained. Since the crosscorrelation for two gold code sequences having a length of 1,023 bits isapproximately 16 times as great as the cross correlation function of anyof the other combinations of gold code sequences, it is relatively easyto lock the locally derived gold code sequence onto the same gold codesequence that was transmitted by one of the satellites.

The gold code sequences from at least four of the satellites in thefield of view of the receiver are separated in this manner by using asingle channel that is sequentially responsive to each of the locallyderived gold code sequences or by using parallel channels that aresimultaneously responsive to the different gold code sequences. Afterfour locally derived gold code sequences are locked in phase with thegold code sequences received from four satellites in the field of viewof the receiver, the position of the receiver can be determined to anaccuracy of approximately 60 to 300 meters.

The approximately 60 to 300 meter accuracy of GPS is determined by (1)the number of satellites transmitting signals to which the receiver iseffectively responsive, (2) the variable amplitudes of the receivedsignals, and (3) the magnitude of the cross correlation peaks betweenthe received signals from the different satellites.

In response to reception of multiple pseudorange noise (PRN) signals,there is a common time interval for some of the codes to likely cause adegradation in time of arrival measurements of each received PRN due tothe cross correlations between the received signals. The time of arrivalmeasurement for each PRN is made by determining the time of a peakamplitude of the cross correlation between the received composite signaland a local gold code sequence that is identical to one of thetransmitted PRN. When random noise is superimposed on a received PRN,increasing the averaging time of the cross correlation between thesignal and a local PRN sequence decreases the average noise contributionto the time of arrival error. However, because the cross correlationerrors between the received PRN's are periodic, increasing the averagingtime increases both signal and the cross correlation value between thereceived PRN's alike and time of arrival errors are not reduced.

The GPS receiver may incorporate a Kalman filter, which is adaptive andtherefore automatically modifies its threshold of acceptable dataperturbations, depending on the velocity of the vehicle (GPS antenna).This optimizes system response and accuracy of the GPS system.Generally, when the vehicle increases velocity by a specified amount,the GPS Kalman filter will raise its acceptable noise threshold.Similarly, when the vehicle decreases its velocity by a specifiedamount, the GPS Kalman filter will lower its acceptable noise threshold.

Extremely accurate GPS receivers depend on phase measurements of theradio carriers that they receive from various orbiting GPS satellites.Less accurate GPS receivers simply develop the pseudoranges to eachvisible satellite based on the time codes being sent. Within thegranularity of a single time code, the carrier phase can be measured andused to compute range distance as a multiple of the fundamental carrierwavelength. GPS signal transmissions are on two synchronous, butseparate, carrier frequencies “L1” and “L2”, with wavelengths ofnineteen and twenty-four centimeters, respectively. Thus within nineteenor twenty-four centimeters, the phase of the GPS carrier signal willchange 360.degree. (2 π radians). However, the number of whole cycle(360.degree.) carrier phase shifts between a particular GPS satelliteand the GPS receiver must be resolved. At the receiver, every cycle willappear essentially the same, over a short time frame. Therefore there isan “integer ambiguity” in the calculation. The resolution of thisinteger ambiguity is therefore a calculation-intensive arithmeticproblem to be solved by GPS receivers. The traditional approaches tosuch integer ambiguity resolution have prevented on-the-fly solutionmeasurement updates for moving GPS receivers with centimeter accurateoutputs. Very often, such highly accurate GPS receivers have requiredlong periods of motionlessness to produce a first and subsequentposition fix.

There are numerous prior art methods for resolving integer ambiguities.These include integer searches, multiple antennas, multiple GPSobservables, motion-based approaches, and external aiding. Searchtechniques often require significant computation time and are vulnerableto erroneous solutions or when only a few satellites are visible. Moreantennas can improve reliability considerably. If carried to an extreme,a phased array of antennas results, whereby the integers are completelyunambiguous and searching is unnecessary. But for economy, reduced size,complexity and power consumption, the minimum number of antennasrequired to quickly and unambiguously resolve the integers, even in thepresence of noise, is preferred.

One method for integer resolution is to make use of the otherobservables that modulate a GPS timer. The pseudo-random code imposed onthe GPS satellite transmission can be used as a coarse indicator ofdifferential range, although it is very susceptible to multipathproblems. Differentiating the L1 and L2 carriers in phase sensitivemanner provides a longer effective wavelength, and reduces the searchspace, i.e., an ambiguity distance increased from 19 or 24 centimetersto about 456 centimeters. However, dual frequency receivers areexpensive because they are more complicated. Motion-based integerresolution methods make use of additional information provided byplatform or satellite motion. But such motion may not always be presentwhen it is needed. Another prior art technique for precision attitudedetermination and kinematic positioning is described by Hatch, in U.S.Pat. No. 4,963,889, incorporated herein by reference, which employs twospaced antennas, moveable with respect to each other. Knight, U.S. Pat.No. 5,296,861, incorporated herein by reference, provides a method ofreducing the mathematical intensity of integer ambiguity resolution. Seealso, U.S. Pat. No. 5,471,218, incorporated herein by reference.

Direct range measurements, combined with the satellite geometry, mayalso allow the correct integer carrier phase ambiguities to bedetermined for a plurality of satellites tracked at two or more sites.The use of additional sensors, such as a laser level, electronicdistance meter, a compass, a tape, etc., provide valuable constraintsthat limit the number of possible integer ambiguities that need to beconsidered in a search for the correct set.

Many systems using handheld computers, having software and databasesdefining maps and running standard operating systems, have been coupledto GPS Smart Antennas. Wireless, infrared, serial, parallel, and PCMCIAinterfaces have been used to interconnect the handheld computer and theGPS Smart Antenna. Differential-ready GPS Smart Antennas having an inputto receive signals representative of DGPS error corrections are alsocommercially available. Further, GPS receivers and Differential-readyGPS Smart Antennas which are self contained, built onto a type II PCMCIAcard (PC Card), and/or having serial data communications ports (RS-232or RS-422) are commercially available. See, U.S. Pat. Nos. 5,276,451,and 5,210,540, assigned to Pioneer Electronic Corporation.

There are several different types of vehicle navigational systems. Thefirst system makes use of stored map displays wherein the maps of apredetermined area are stored in the in-vehicle computer and displayedto the vehicle operator or driver. The maps, combined with informationdescribing the location where the vehicle started and where it is to go,will highlight the direction and the driver will have to read thedisplay and follow the route. One such stored map display system wasoffered by General Motors on their 1994 Oldsmobile, using GlobalPositioning System (GPS) satellites and dead reckoning techniques, andlikely map matching to determine a precise location. The vehicle hasradio receivers for receiving data from satellites, giving the locationof the receiver expressed in latitude and longitude. The driver entersdetails of the desired destination into an on-board or in-vehiclecomputer in the form of specific address, a road intersection, etc. Thestored map is displayed, allowing the operator to pinpoint the desireddestination. The on-board computer then seeks to calculate the mostefficient route, displaying the distance to, and the direction of, eachturn using graphics and a voice prompt.

Other known systems employ speech recognition as a user input. Forexample, another system, described in U.S. Pat. No. 5,274,560 does notuse GPS and has no sensing devices connected to the vehicle. The routinginformation is contained in a device that is coupled to a CD player inthe vehicle's audio system. Commands are entered into the system via amicrophone and the results are outputted through the vehicle's speakers.The vehicle operator spells out the locations and destinations, letterby letter. The system confirms the locations by repeating whole words.Once the system has received the current location and destination, thesystem develops the route and calculates the estimated time. Theoperator utilizes several specific performance commands, such as “Next”,and the system then begins to give segment by segment route directions.

Still another system, such as the Siemens Ali-Scout™ system, requiresthat the driver key-in the destination address coordinates into thein-vehicle computer. A compass located in the vehicle then gives a“compass” direction to the destination address. Such a compass directionis shown in graphics as an arrow on a display unit, indicating thedirection the driver should go. Along the side of the road are severalinfrared beacon sites which transmit data information to a properlyequipped vehicle relative to the next adjacent beacon site. From all ofthe information received, the in-vehicle computer selects the desiredbeacon data information to the next beacon and displays a graphic symbolfor the vehicle operator to follow and the distance to the desireddestination. In this system, there is no map to read; both a simplegraphic symbol and a segment of the route is displayed, and a voiceprompt telling the vehicle operator when to turn and when to continue inthe same direction is enunciated. Once the program begins, there isminimal operator feedback required.

U.S. Pat. No. 4,350,970, describes a method for traffic management in arouting and information system for motor vehicle traffic. The system hasa network of stationary routing stations each located in the vicinity ofthe roadway, which transmit route information and local informationconcerning its position to passing vehicles. The trip destinationaddress is loaded by the vehicle operator into an onboard device in thevehicle and by dead reckoning techniques, a distance and directiongraphic message is displayed. The first routing station which thevehicle passes transmits a message to the vehicle with route data to thenext routing station. The vehicle receives the message and as itexecutes the several vector distances in the message, it accumulatestime and distance which it then transmits to the second routing stationwhen it is interrogated by the second routing station. In this manner,traffic management is updated in real time and the vehicles are alwaysrouted the “best way”. Of course, the best way may be the shortest way,the less traveled way, the cheapest way or any combination of these plusother criteria. See also, U.S. patent application Ser. No. 08/258,241,filed on Aug. 3, 1994.

U.S. Pat. No. 5,668,880, incorporated herein by reference, relates to anintervehicle data communication device.

Systems which integrate GPS, GLONASS, LORAN or other positioning systemsinto vehicular guidance systems are well known, and indeed navigationalpurposes were prime motivators for the creation of these systems. Radar,laser, acoustic and visual sensors have all been applied to vehicularguidance and control, as well. For example, U.S. Pat. No. 4,757,450relates to a reflected beam system for detecting a preceding vehicle, inorder to allow control over intervehicular spacing. U.S. Pat. No.4,833,469 relates to an obstacle proximity sensor, employing, e.g., aradar beam to determine distance and relative velocity of an obstacle.U.S. Pat. No. 5,600,561 relates to a vehicle distance data processorwhich computes a velocity vector based on serial timepoints. U.S. Pat.No. 4,552,456 relates to an optical pulse radar for an automobile. U.S.Pat. No. 4,543,577 relates to a moving obstacle detection system for avehicle, using Doppler radar. U.S. Pat. No. 4,349,823 relates to anautomotive radar system for monitoring objects in front of the vehicle.U.S. Pat. No. 5,473,538 relates to a collision judging system for avehicle, triggered by a braking event and determining a distance to anobstacle in front of the vehicle. U.S. Pat. No. 4,168,499 relates to ananti-collision radar system. U.S. Pat. No. 4,626,850 relates to avehicle detection and collision avoidance apparatus, using an acousticsensor. U.S. Pat. No. 4,028,662 relates to a passing vehicle signalingapparatus, to detect adjacent vehicles during a lane change. U.S. Pat.No. 5,541,590 relates to a vehicle crash predictive and evasive system,employing neural networks. U.S. Pat. No. 5,646,612 relates to a vehiclecollision avoidance system, using an infrared imaging system. U.S. Pat.No. 5,285,523 relates to a neural network system for recognizing drivingconditions and controlling the vehicle in dependence thereon. U.S. Pat.No. 5,189,619 relates to an artificial intelligence based adaptivevehicle control system. U.S. Pat. No. 5,162,997 relates to adriver-adaptive automobile control system. U.S. Pat. No. 3,689,882relates to an anti-collision radar system for detecting obstacles oron-coming vehicles.

U.S. Pat. No. 4,855,915 relates to a vehicle which may be autonomouslyguided using optically reflective materials. U.S. Pat. No. 5,347,456relates to an intelligent roadway reference system for controllinglateral position of a vehicle, using magnetic sensors. U.S. Pat. No.5,189,612 relates to an autonomous vehicle guidance system employingburied magnetic markers. U.S. Pat. No. 5,039,979 relates to a roadwayalarm system employing metallized painted divider lines. U.S. Pat. No.4,239,415 relates to a method for installing an electromagnetic sensorloop in a highway. U.S. Pat. No. 4,185,265 relates to a vehicularmagnetic coded signaling apparatus which transmits binary signals usingmagnetic signposts. U.S. Pat. No. 5,687,215 relates to a vehicularemergency message system. U.S. Pat. No. 5,550,055 relates to a positionmonitoring system for vehicles, for example in case they are stolen.U.S. Pat. No. 5,563,071 relates to a system for time and/or eventlogging of an event, employing differential GPS. U.S. Pat. No. 5,701,328relates to a chirped spread spectrum positioning system.

U.S. Pat. Nos. 5,689,269, 5,119,504, 5,678,182, 5,621,793, 5,673,305,5,043,736, 5,684,860, 5,625,668, 5,602,739, 5,544,225, 5,461,365,5,299,132, 5,301,368, 5,633,872, 5,563,607, 5,382,957, 5,638,078,5,630,206, 5,610,815, 4,677,555, 4,700,301, 4,807,131, 4,963,889,5,030,957, 5,144,317, 5,148,179, 5,247,306, 5,296,861, 5,347,286,5,359,332, 5,442,363, 5,451,964, expressly incorporated herein byreference, relate to systems which employ GPS and telecommunicationfunctionality. Such systems are often employed in differential globalpositioning system (DGPS) and vehicular security and trackingapplications.

Typical “secure” encryption systems include the Rivest-Shamir-Adelmanalgorithm (RSA), the Diffie-Hellman algorithm (DH), the Data EncryptionStandard (DES), elliptic curve encryption algorithms, so-called PGPalgorithm, and other known algorithms. U.S. Pat. Nos. 4,200,770,4,218,582, 4,405,829, 4,424,414 and 4,424,415, expressly incorporatedherein by reference, relate to RSA-type encryption systems. Othercryptographic system patents include U.S. Pat. Nos. 4,658,094 and4,797,920, incorporated herein by reference. See also:

“A Method for Obtaining Digital Signatures and Public-KeyCryptosystems.” By R. L. Rivest, A. Shamir, and L. Adelman,Communication of the ACM, February 1978, Volume 21 Number 2. Pages120-126.

The Art of Computer Programming, Volume 2: Seminumerical Algorithms, ByD. E. Knuth, Addison-Wesley, Reading, Mass. 1969.

“The First Ten Years of Public Key Cryptography”, By Whitfield Diffie,Proceedings of the IEEE, Volume 6 Number 5, May 1988, Pages 560-577.

U.S. Pat. Nos. 4,668,952; 4,698,632; 4,700,191; 4,709,407; 4,725,840;4,750,215; 4,791,420; 4,801,938; 4,805,231; 4,818,997; 4,841,302;4,862,175; 4,887,068; 4,939,521; 4,949,088; 4,952,936; 4,952,937;4,954,828; 4,961,074; 5,001,777; 5,049,884; 5,049,885; 5,063,385;5,068,663; 5,079,553; 5,083,129; 5,122,802; 5,134,406; 5,146,226;5,146,227; 5,151,701; 5,164,729; 5,206,651; 5,239,296; 5,250,951,5,268,689; 5,270,706; 5,300,932; 5,305,007; 5,315,302; 5,317,320;5,331,327; 5,341,138; 5,347,120; 5,363,105; 5,365,055; 5,365,516;5,389,930; 5,410,750; 5,446,923; 5,448,638; 5,461,383; 5,465,413;5,513,110; 5,521,696; 5,525,989; 5,525,996; 5,528,245; 5,528,246;5,529,139; 5,510,793; 5,529,139; 5,610,815, expressly incorporatedherein by reference, relate to radar and radar detection andidentification systems, and associated technologies.

U.S. Pat. No. 5,519,718, incorporated herein by references, relates to amobile bidirectional pager communication scheme. U.S. Pat. No.5,218,620, incorporated herein by references, relates to a spreadspectrum communication device.

U.S. Pat. Nos. 3,161,871; 3,568,161; 3630079; 3,664,701; 3,683,114;3,769,710; 3,771,483; 3,772,688; 3,848,254; 3,922,673; 3,956,797;3,986,119; 3,993,955; 4,002,983; 4,010,619; 4,024,382; 4,077,005;4,084,323; 4,114,155; 4,152,693; 4,155,042; 4,168,576; 4,229,620;4,229,737; 4,235,441; 4,240,079; 4,244,123; 4,274,560; 4,313,263;4,323,921; 4,333,238; 4,359,733; 4,369,426; 4,384,293; 4,393,270;4,402,049; 4,403,291; 4,428,057; 4,437,151; 4,445,118; 4,450,477;4,459,667; 4,463,357; 4,471,273; 4,472,663; 4,485,383; 4,492,036;4,508,999; 4,511,947; 4,514,665; 4,518,902; 4,521,885; 4,523,450;4,529,919; 4,547,778; 4,550,317; 4,555,651; 4,564,085; 4,567,757;4,571,847; 4,578,678; 4,591,730; 4,596,988; 4,599,620; 4,600,921;4,602,279; 4,613,867; 4,622,557; 4,630,685; 4,633,966; 4,637,488;4,638,445; 4,644,351; 4,644,368; 4,646,096; 4,647,784; 4,651,157;4,652,884; 4,654,879; 4,656,463; 4,656,476; 4,659,970; 4,667,203;4,673,936; 4,674,048; 4,677,555; 4,677,686; 4,678,329; 4,679,147;4,680,715; 4,682,953; 4,684,247; 4,688,244; 4,690,610; 4,691,149;4,691,385; 4,697,281; 4,701,760; 4,701,934; 4,703,444; 4,706,772;4,709,195; 4,713,767; 4,718,080; 4,722,410; 4,727,492; 4,727,962;4,728,922; 4,730,690; 4,731,613; 4,740,778; 4,741,245; 4,741,412;4,743,913; 4,744,761; 4,750,197; 4,751,512; 4,751,983; 4,754,280;4,754,283; 4,755,905; 4,758,959; 4,761,742; 4,772,410; 4,774,671;4,774,672; 4,776,750; 4,777,818; 4,781,514; 4,785,463; 4,786,164;4,790,402; 4,791,572; 4,792,995; 4,796,189; 4,796,191; 4,799,062;4,804,893; 4,804,937; 4,807,714; 4,809,005; 4,809,178; 4,812,820;4,812,845; 4,812,991; 4,814,711; 4,815,020; 4,815,213; 4,818,171;4,819,053; 4,819,174; 4,819,195; 4,819,860; 4,821,294; 4,821,309;4,823,901; 4,825,457; 4,829,372; 4,829,442; 4,831,539; 4,833,477;4,837,700; 4,839,835; 4,846,297; 4,847,862; 4,849,731; 4,852,146;4,860,352; 4,861,220; 4,864,284; 4,864,592; 4,866,450; 4,866,776;4,868,859; 4,868,866; 4,869,635; 4,870,422; 4,876,659; 4,879,658;4,882,689; 4,882,696; 4,884,348; 4,888,699; 4,888,890; 4,891,650;4,891,761; 4,894,655; 4,894,662; 4,896,370; 4,897,642; 4,899,285;4,901,340; 4,903,211; 4,903,212; 4,904,983; 4,907,159; 4,908,629;4,910,493; 4,910,677; 4,912,475; 4,912,643; 4,912,645; 4, 14,609;4,918,425; 4,918,609; 4,924,402; 9 4,924,417; 4,924,699; 4,926,336;4,928,105; 4,928,106; 4,928,107; 4,932,910; 4,937,751; 4,937,752;4,939,678; 4,943,925; 4,945,501; 4,947,151; 4,949,268; 4,951,212;4,954,837; 4,954,959; 4,963,865; 4,963,889; 4,968,981; 4,970,652;4,972,431; 4,974,170; 4,975,707; 4,976,619; 4,977,679; 4,983,980;4,986,384; 4,989,151; 4,991,304; 4,996,645; 4,996,703; 5,003,317;5,006,855; 5,010,491; 5,014,206; 5,017,926; 5,021,792; 5,021,794;5,025,261; 5,030,957; 5,030,957; 5,031,104; 5,036,329; 5,036,537;5,041,833; 5,043,736; 5,043,902; 5,045,861; 5,046,011; 5,046,130;5,054,110; 5,055,851; 5,056,106; 5,059,969; 5,061,936; 5,065,326;5,067,082; 5,068,656; 5,070,404; 5,072,227; 5,075,693; 5,077,557;5,081,667; 5,083,256; 5,084,822; 5,086,390; 5,087,919; 5,089,826;5,097,269; 5,101,356; 5,101,416; 5,102,360; 5,103,400; 5,103,459;5,109,399; 5,115,223; 5,117,232; 5,119,102; 5,119,301; 5,119,504;5,121,326; 5,122,803; 5,122,957; 5,124,915; 5,126,748; 5,128,874;5,128,979; 5,144,318; 5,146,231; 5,148,002; 5,148,179; 5,148,452;5,153,598; 5,153,836; 5,155,490; 5,155,491; 5,155,591; 5,155,688;5,155,689; 5,157,691; 5,161,886; 5,168,452; 5,170,171; 5,172,321;5,175,557; 5,177,685; 5,184,123; 5,185,610; 5,185,761; 5,187,805;5,192,957; 5,193,215; 5,194,871; 5,202,829; 5,208,756; 5,210,540;5,210,787; 5,218,367; 5,220,507; 5,220,509; 5,223,844; 5,225,842;5,228,695; 5,228,854; 5,245,537; 5,247,440; 5,257,195; 5,260,778;5,265,025; 5,266,958; 5,269,067; 5,272,483; 5,272,638; 5,274,387;5,274,667; 5,276,451; 5,278,424; 5,278,568; 5,292,254; 5,293,318;5,305,386; 5,309,474; 5,317,321; 5,319,548; 5,323,322; 5,324,028;5,334,974; 5,334,986; 5,347,285; 5,349,531; 5,364,093; 5,365,447;5,365,450; 5,375,059; 5,379,224; 5,382,957; 5,382,958; 5,383,127;5,389,934; 5,390,125; 5,392,052; 5,400,254; 5,402,347; 5,402,441;5,404,661; 5,406,491; 5,406,492; 5,408,415; 5,414,432; 5,416,712;5,418,537; 5,418,538; 5,420,592; 5,420,593; 5,420,594; 5,422,816;5,424,951; 5,430,948; 5,432,520; 5,432,542; 5,432,841; 5,433,446;5,434,574; 5,434,787; 5,434,788; 5,434,789; 5,519,403; 5,519,620;5,519,760; 5,528,234; 5,528,248; 5,565,874 and Re32856, expresslyincorporated herein by reference, relate to GPS systems and associatedtechnologies.

Foreign patent references CA 1298387, 19920300; CA 1298903, 19920400; CA2009171/1990 02; DE 3310111, 19840900; DE 3325397/1985 01; DE 3419156,19840500; DE 3538908A1, 19870500; DE 4123097; EP 0155776/1990 08; EP0158214, 19851000; EP 0181012, 19860500; EP 0290725/1992 09; EP 0295678,19880600; EP 0309293A2, 19890300; EP 0323230, 19890500; EP 0323246,19890700; EP 0348528, 19900100; EP 0393935, 19901000; EP 0444738,19910900; EP 0485120, 19920500; EP 0501058/1991 04; EP 0512789,19921100; FR 2554612, 19850500; GB 2079453, 19820100; GB 211204,19830600; GB 2126040, 19870100; GB 2238870, 19891100; GB 2256987; JP57-32980, 19820200; JP 63-26529, 19840200; JP 1130299, 19871100; JP1136300, 19871100; JP 153180, 19890300; JP 63188517, 19890500; JP0189414, 19900700; JP 2212713, 19900800; JP 02-243984, 19900900; JP03-17688, 19910100; JP 3-080062, 1991 04 12; JP 3-080063, 1991 04 12; JP0078678, 19910400; JP 0092714, 19910400; JP 1272656, 19910900; JP03245075, 19911000; JP 3245076, 19911000; JP 63-12096; JP 221093; WO87/06713, 19871100; WO 92/08952, 19920500; WO 93/09510, 19930500; WO87/07056, 19871100 and WO 91/05429, incorporated herein by reference,relate to GPS and related technologies.

The following references, incorporated herein by reference, relate toGPS, position sensors, sensor data analysis, and associatedtechnologies:

“Fuzzy Logic Simplifies Complex Control Problems”, Tom Williams,Computer Design, Mar. 1, 1991.

“Methods for Performance Evaluation of Coordinate Measuring Machines,ANSFASME B89.1.12M-1985,” An American National Standard, published byThe American Society of Mechanical Engineers, USA, 1985.

“Neural Network And Fuzzy Systems—A Dynamical Systems Approach ToMachine Intelligence”, Bart Kosko; Prentice Hall 1992; Englewood Cliffs,N.J.; pp. 13, 18, 19. “New Airbuses to Use Laser Inertial ReferenceSystems for Navigation,” Litton Systems, Aircraft Engineering, pp.10-11, June 1983.

“Reasoning For Interpreting Sensor Data,” P. J. Braspenning,International Conference Intelligent Autonomous Vehicles, Amsterdam,1986.

“Sensor Failure Detection Using a Hybrid Analytical/IntelligentAlgorithm,” George Vachstevanos, International Conference IntelligentAutonomous Vehicles, Amsterdam, 1986. “An/PRC-112 Multi-MissionTransceiver”, published by Motorola, Inc., Communications Division,Copyright 1991.

“Combat Rescue. One Pass is All You Get. With PLS, One Pass is All YouNeed. PLS (Personnel Locator System)”, published jointly by CubicDefense Systems and Motorola, Inc., publication date unknown.

“Artificial intelligence in the control and operation of constructionplant-the autonomous robot excavator” published 1993.

“Automation and Robotics in Construction”—vol. 1 by FHG (9 pgs.)believed to have been published on or about June 1991.

“Backhoe Monitor” by IHC-3 Pgs.—Publication date unknown but believed tobe prior to one year before the filing date.

Ashjaee, J., et al., “Precise Positioning Using a 4-Channel C/A Code GPSReceiver,” IEEE pp. 236-244, 1984.

Auch, W., et al., “Fibre Optic Gyroscope,” 1984.

B. Krogh et al., “Integrated Path Planning and Dynamic Steering Controlfor Autonomous Vehicles,” 1986.

Brockstein, A., “GPS-Kalman-Augmented Inertial Navigation SystemPerformance,” Naecom '76 Record, pp. 864-868, 1976.

Brodie, K., et al., Performance Analysis of Integrated NavigationSystems, computer applications software technology, no date.

Brooks, R., “Solving the Fine-Path Problem by Good Representation ofFree Space,” IEEE Transactions on Systems, Man, and Cybernetics, pp.190-197, March-April, 1983.

Brown, R., “Kalman Filtering Study Guide—A Guided Tour,” Iowa StateUniversity, pp. 1-19, 1984.

Brown, R., Random Signal Analysis & Kalman Filtering, Chapter 5, pp.181-209, no date.

Bundorf, R. “The Influence of Vehicle Design Parameters onCharacteristic Speed and Understeer,” January 1967.

C. McGillem et al., “Infra-Red Location System for Navigation ofAutonomous Vehicles,” IEEE, pp. 1236-1238, 1988.

Canny, J., “A Computational Approach to Edge Detection,” pp. 184-203,1985.

Culshaw, B., et al., “Fibre Optic Gyroscopes In Inertial Navigation,” nodate.

D. Daniel et al., “Kinematics and Open-loop Control of an Ilonator-BasedMobile Platform,” pp. 346-351 1985.

D. Feng, “Satisficing Feedback Strategies for Local Navigation ofAutonomous Mobile Robots,” May 5, 1989.

D. Kriegman et al., “Generic Models for Robot Navigation,” pp. 746-751,1988.

D. Kuan et al., “Model-based Geometric Reasoning for Autonomous RoadFollowing,” pp. 416-423, 1987.

D. Kuan, “Autonomous Robotic Vehicle Road Following,” IEEE Transactionson Pattern Analysis and Machine Intelligence, pp. 647-658, 1988.

D. Rogers et al., Mathematical Elements for Computer Graphics, pp.144-155, Dec. 8, 1989.

D. Touretzky et al., “What's Hidden in the Hidden Layers?,” Byte, pp.227-233, August 1989.

Data Fusion in Pathfinder and Travtek, Roy Sumner, VNIS '91 conference,October 20-23, Dearborn, Mich.

Database Accuracy Effects on Vehicle Positioning as Measured by theCertainty Factor, R. Borcherts, C. Collier, E. Koch, R. Bennet, VNIS '91conference from October 20-23, Dearborn, Mich.

Daum, F., et al., “Decoupled Kalman Filters for Phased Array RadarTracking,” IEEE Transactions on Automatic Control, pp. 269-283, March1983.

Denavit, J. et al., “A Kinematic Notation for Lower-Pair MechanismsBases on Matrices,” pp. 215-221, June, 1955.

Dickmanns, E. et al., “Guiding Land Vehicles Along Roadways by ComputerVision”, The Tools for Tomorrow, Oct. 23, 1985.

Dickmans, E., “Vehicle Guidance by Computer Vision,” no date.

Divakaruni, S., et al., “Fast Reaction and High Reliability of StrapdownNavigation Systems Using Ring Laser Gyros,” IEEE pp. 315-322, 1984.

E. Dickmanns et al., “A Curvature-based Scheme for Improving RoadVehicle Guidance by Computer Vision,” SPIE's Cambridge Symposium onOptical and Optoelectronic Engineering, October 1986.

E. Udd, “Fiberoptic v. Ring Laser Gyros: An Assessment of theTechnology,” Laser Focus/Electro-Optics, pp. 64-74, December 1985.

Edward J. Krakiwsky, “A Kalman Filter for Integrating Dead Reckoning,Map Matching and GPS Positioning”, IEEE Plans '88 Position Location andNavigation Symposium Record, Kissemee, Fla. USA, 29 Nov. 2-December1988, pp. 39-46.

Euler, W., et al., “A Perspective on Civil Use of GPS, The Institute ofNavigation, 36th Annual Meeting, pp. 1-7, 1980.

Fusion of Multisensor Data, John M. Richardson, Kenneth A. Marsh;International Journal of Robotics Research; vol. 7, no. 6; December1988; pp. 78-87.

Fuzzy Systems and Applications, United Signals and Systems, Inc., BartKosko with Fred Watkins, Jun. 5-7, 1991.

G. Geier, et al., “Design of an Integrated Navigation System for RoboticVehicle Application,” Journal of the Institute of Navigation.

G. Wilfong, “Motion Planning for an Autonomous Vehicle,” AT&T BellLaboratories, pp. 529-533, 1988.

GPS Technology and Opportunities, Clyde Harris and Roy Sikorski ExpoComm China '92, Beijing, China, Oct. 30-Nov. 4, 1992.

GPS World, News and Applications of the Global Positioning System,March/April 1990. GPS-90 Tutorials, The Institute of Navigation, Sep.17-18, 1990, pp. 1-28.

Greenspan, R., et al. “Accuracy of Relative Positioning byInterferometry with Reconstructed Carrier CPS: Experimental Results,”Third International Symposium on Satellite Doppler Positioning, pp.1-19, February/1982.

H. Hatwal et al., “Some Inverse Solutions to an Automobile Path-trackingProblem with Input Control of Steering and Brakes,” Vehicle SystemDynamics, pp. 61-71, 1986.

H. Nasr et al., “Landmark Recognition for Autonomous Mobile Robots,” pp.1218-1223, 1988.

H. Nii, “Blackboard Application Systems, Blackboard Systems from aKnowledge Engineering Perspective,” The AI Magazine, pp. 82-89, August1986.

H. Nii, “Blackboard Systems: The Blackboard Model Problem-solving andthe Evolution of Blackboard Architectures,” The AI Magazine, pp. 38-53,Summer 1986.

H. Wunsche, “Detection and Control of Mobile Robot Motion by Real-TimeComputer Vision,” Mobile Robots, pp. 100-104, 1986.

H. Yamazaki et al., “Autonomous Land Vehicle Using Millimeter WaveSensing Systems,” Proceedings of the 5th International Symposium onRobotics in Construction, June 1988.

Hiroshige et al., “Error Analysis of Electronic Roll Stabilization forElectronically Scanned Antennas”, IEEE 1991 pp. 71-75.

I. Cox, “Blanche: An Autonomous Robot Vehicle for StructuredEnvironments,” AT&T Bell Laboratories, pp. 978-982, 1988.

IEEE Communications Magazine, vol. 26, No. 7, July 1988 (New York) P.Enge et al. “Differential operation of global positioning system” pp.48-59.

IEEE Journal of Robotics & Automation, vol. 4, No. 3, June 1988, IEEE(New York), C. Isik et al. “Pilot Level of a Hierarchical Controller foran Unmanned Mobile Robot”, pp. 241-255.

IEEE Journal of Robotics & Automation, vol. 4, No. 4, August 1988, IEEE(New York) J. LeM “Domain-dependent reasoning for visual navigation ofroadways, pp. 419-427 (Nissan) Mar. 24, 1988.

IEEE Plans '86 Position Location and Navigation Symposium, November1986, S. Bose: “GPS/PLRS aided inertial land navigation systemperformance”, pp. 496-504.

IEEE Plans '86 Position Location and Navigation Symposium. November1986, S. Bose: “GPS/PLRS aided inertial land navigation systemperformance”, pp. 496-504.

IEEE Plans '90 Position Location and Navigation Symposium, Las Vegas,Mar. 20-23, 1990, IEEE New York, N.Y., US. Hunter et al: ‘Vehiclenavigation using differential GPS’, pp. 392-398.

IEEE Proceedings, vol. 77, No. 11, Nov. 11, 1989, L. Schuchman et al.:“Applicability of an augmentated GPS for navigation in the NationalAirspace system”, pp. 1709-1727, 1713, 1717, FIGS. 1-8.

IEEE Transactions on Pattern Analysis, vol. 10, No. 5 Sep. 1988, IEEE(New York), D. Kuan et al., “Autonomous robotic vehicle road following”pp. 648-658.

Iijima, J., et al., “A Locomotion Control System for Mobile Robots,” nodate.

Integration of GPS and Dead Reckoning Navigation Systems, Wei-Wen Kao,VNIS '91 conference from October 20-23, Dearborn, Mich.

J. Borenstein et al., “The Vector Field Histogram-Fast ObstacleAvoidance for Mobile Robots,” IEEE Journal of Robotics and Automation,July 1989.

J. Collins, “GPS Equipment Survey, GPS-What does it all mean?,” P.O.B.,June-July 1987 pp. 12-22.

J. Crowley, “Asynchronous Control of Orientation and Displacement in aRobot Vehicle,” pp. 1277-1288, 1989.

J. Crowley, “Part 3: Knowledge Based Supervision of Robotics Systems,”1989 IEEE Conference on Robotics and Automation, pp. 37-42, 1989.

J. Dixon, “Linear and Non-linear Steady State Vehicle Handling,”Proceedings of the Institute of Mechanical Engineers, pp. 173-186, 1988.

J. Nielson, et al. “GPS Aided Inertial Navigation,” IEEE AES Magazine,pp. 20-26, March 1986.

J. Oliver et al., “A Navigation Algorithm for an Intelligent Vehiclewith a Laser Rangefinder,” pp. 1145-1150, 1986.

J. Sennott et al., “Study of Differential Processing and KalmanFiltering of Bay Saint Louis Test Data, Ch 1-5, 1987.

Jacob, T., Integrated Navigation System for Approach Guidance forRegional Air-Traffic Using GPS, no date.

Johnson, C. “In-Flight Transfer Alignment/Calibration of a Strapdown INSthat Employs Carouseled Instruments and IMV Indexing,” no date.

Jorgensen, “18-Satellite Constellations,” pp. 9-12, 1980.

Kaczmarek, K. W., “Cellular Networking: A Carrier's Perspective”, 39thIEEE Vehicular Technology Conference, May 1, 1989, vol. 1, pp. 1-6.

Kanayama, Y., et al., “A Vehicle Control Architecture-Smooth Driver,”Stanford University, no date.

Kanayama, Y., et al., “Trajectory Generation for Mobile Robots,” nodate.

Kao, M., et al., “Multiconfiguration Kalman Filter Design forHigh-Performance GPS Navigation,” IEEE Transactions on AutomaticControl, pp. 304-314, March 1983.

Khatib, O., “Real-time Obstacle Avoidance for Manipulators and MobileRobots”, pp. 500-505, 1985.

Knowledge Representation in Fuzzy Logic, Lotfi A. Zadeh, IEEETransactions on Knowledge and Data Engineering, vol. 1, No. 1, March1989.

Kowalski et al., “Music Algorithm Implementation for Shipboard HF RadioDirection Finding”, IEEE, 1991, pp. 0943-0947.

Kuritsky, M., et al., “Inertial Navigation,” Proceedings of the IEEE,pp. 1156-1176, October 1983.

L. Matthies et al., “Integration of Sonar and Stereo Range Data Using aGrid-based Representation,” Computer Science Department and RoboticsInstitute, Carnegie-Mellon University, pp. 727-733, 1988.

Lerner, E., “Gyros in Business Aircraft,” Aerospace America, pp. 66-69,October 1984.

Lozano-Perez, T., et al., “An Algorithm for Planning Collision-freePaths among Polyhedral Obstacles,” Communications of the ACN, pp.560-570, October 1979.

Luh, J., et al., “Resolved-acceleration Control of MechanicalManipulators,” IEEE Transactions on Automatic Control, pp. 468-475, June1980.

M. Dailey et al., “Autonomous Cross-Country Navigation with the ALV,”Hughes Artificial Intelligence Center, pp. 718-726, 1988.

M. Grewal et al., “Application of Kalman Filtering to the Calibrationand Alignment of Inertial Navigation Systems,” IEEE, pp. 65-72, 1986.

MacAdam, C., “Application of an Optimal Preview Control for Simulationof Closed-Loop Automobile Driving,” IEEE Transactions on Systems, Man,and Cybernetics, pp. 393-399, June 1981.

Martin, E., “Aiding GPS Navigation Functions,” Naecom '76 Record, pp.849-856, 1976.

Mueller, C., et al., “Laser Gyro Land Navigation System PerformancePredictions and Field Results,” IEEE, 1984.

Navigation “Surveys” Summer, 1984, vol. 31, #2, by P. F. MacDoran et al.Navigation Journal of The Institute of Navigation, vol. 32, No. 4,Winter, 1985-86, Printed in U.S.A., “Terrestrial Evaluation of the GPSStandard Positioning Service”: by Francis W. Mooney.

Navigation Journal of the Institute of Navigation, vol. 33, No. 4,Winter, 1986-87, Printed in U.S.A., “DiffStar: A Concept forDifferential GPS in Northern Norway”, by Hermod Fjereide.

Navigation Journal of the Institute of Navigation, vol. 36, No. 3, Fall,1989, Printed in U.S.A., “Loran-C Vehicle Tracking in Detroit's PublicSafety Dispatch System”, by Laurence J. Cortland.

Naystar GPS Space Segment/Navigation User Interface, RockwellInternational Corporation, Nov. 30, 1987.

Nedley, A., et al., “A New Laboratory Facility for Measuring VehicleParameters Affecting Understeer and Brakesteer,” pp. 1-20, Jun. 2, 1972.

Nitao, J., et al., “A Pilot for a Robotic Vehicle System,” pp. 951-955,no date. Orin, D., “Supervisory Control of a Multi-legged Robot,” TheInternational Journal of Robotics Research, pp. 79-91, Spring 1982.

P. Muir, et al. “Kinematic Modeling for Feedback Control of anOmnidirectional Wheeled Mobile Robot,” pp. 1772-1778, 1987.

Parkinson, B., et al., “NAVSTAR: Global Positioning System—Ten YearsLater,” Proceedings of the IEEE, pp. 1178-1186, 1983.

Patent Abstract of Japan, vol. 12, No. 290 (p. 742) Aug. 8, 1988 & JPA63066479 (Nissan) Mar. 24, 1988.

Patent Abstract of Japan, vol. 13, No. 306 (p. 897) Jul. 13, 1989 & JPA1079679 (Toyota) Mar. 24, 1989.

Patent Abstract of Japan, vol. 13, No. 306 (p. 897) Jul. 7, 1989 & JPA1079679 (Toyota) Mar. 24, 1989.

Proceeding PR '88, The Computer Society Conference on Computer Vision &Pattern Recognition, Jun. 5-9, 1988 (Ann Arbor) S. Dickinson et al., “Anexpert vision system for Autonomous Land Vehicle Road Following”, pp.826-831.

Proceedings 1987 IEEE Conference Mar. 31-Apr. 3, 1987, vol. 2, L. Conwayet al.: “Teleautonomous systems: Methods & Architectures forIntermingling autonomous & Telerobotic Technology” pp. 1121 1130.

Proceedings 1987 IEEE International Conference on Robotics & Automation,Mar. 31-Apr. 3, 1987. (Raleigh, N.C.), sponsored by IEEE Council onRobotics & Automation, vol. 3, D. McMenthon, “A zero-bank algorithm forInverse Perspective of a Road from Single Image, pp. 1444-1449.

Proceedings of 1988 IEEE International Conference on Robotics &Automation, vol. 2, Apr. 24-29, 1988, Philadelphia, IEEE Computer Soc.Press (Washington D.C.), L. E. Banta: “A self turning navigationalgorithm”, pp. 1313-1314.

Proceedings of the IEEE-F Communications, Radar and Signal Processing,vol. 127, No. 2 Apr. 1980, Stevenage, G B. Blair et al: ‘receivers forthe NAVSTAR global positioning system’, pp. 163-167.

Product Announcement, “Measurement Methods-Coordinate MeasuringSpecialists,” published by Measurement Methods, Baltimore, Md., USA,publication date unknown. Product Brochure entitled “KOBA-Step PrecisionStep Gauge,” published by Kolb & Baumann GmbH & Co., Germany, 1992.

Product Brochure, “Mobile Calibration Station Utilizing SurveillanceMasters,” published by Glastonbury Gage, USA, publication date unknown.

R. Cox et al., “Design for Maintainability: Litton's New Family of RLGInertial Navigation Systems,” IEEE, pp. 115-119, 1986.

R. Dork, “Satellite Navigation Systems for Land Vehicles,” IEEE AESMagazine, pp. 2-5, May 1987.

R. Dunlay, “Obstacle Avoidance Perception Processing for the AutonomousLand Vehicle,” pp. 912-917, 1988.

R. Majure et al., “Comparison of Laser Gyro IMU Configurations forReentry Systems,” IEEE, pp. 96-100, 1986.

Randolph Hartman, “Integrated Laser Inertial/GPS Navigation (GPIRS),“Publication of Honeywell Inc., February, 1990, from a presentation ofthe Royal Institute of Navigation NAV '89” Satellite NavigationConference, October, 1989.

Raol, J., et al., “On the Orbit Determination Problem,” IEEETransactions on Aerospace and Electronic Systems, pp. 274-290, May 1985.

Richardson, Rick, “Standards try to help-but don't always agree,”Quality Magazine, USA, publication date unknown.

S. Divakaruni et al., “Ring Laser Gyro Inertial and GPS IntegratedNavigation System for Commercial Aviation,” IEEE, pp. 73-80, 1986.

Sakai, H., “Theoretical and Experimental Studies on the DynamicProperties of Tyres Part I: Review of Rubber Friction,” InternationalJournal of Vehicle Design, pp. 78-110, 1981.

Sakai, H., “Theoretical and Experimental Studies on the DynamicProperties of Tyres, Part II: Experimental Investigation of RubberFriction and Deformation of a Tyre,” International Journal of VehicleDesign, pp. 182-226, 1981.

Sakai, H., “Theoretical and Experimental Studies on the DynamicProperties of Tyres, Part III: Calculation of the Six Components ofForce and Moment of Tyre,” International Journal of Vehicle Design, pp.335-372, 1981.

Savkoor, A. R., “The Lateral Flexibility of Pneumatic Tyre and ItsApplication to the Lateral Rolling Contact Problem, ” pp. 367-381, nodate.

Schwartz, H., “Sensitivity Analysis of an Integrated Naystar GPS/INSNavigation System to Component Failure,” Journal of the Institute ofNavigation, vol. 3, No. 4, pp. 325-337, 1983.

Sennott, J. W., “Experimental Measurement and Characterization ofIonospheric Multipath Errors In Differential GPS”, no date.

Sennott, J., “Real-Time GPS and Loran-C Dynamical Performance forCritical Marine Applications,” IEEE, pp. 1006-1009, 1981.

Sennott, J., et al., “A Queuing Model for Analysis of A BurstyMultiple-Access Communication Channel,” IEEE, pp. 317-321, 1981.

Sheridan, T. “Three Models of Preview Control,” IEEE Transactions onHuman Factors in Electronics, pp. 91-102, June 1966.

Sheth, P., et al., “A Generalized Symbolic Notation for Mechanism,”Transactions of the ASME, pp. 102-112, February 1971.

Sorenson, W., “Least-Squares estimation: From Gauss to Kalman,” IEEESpectrum, pp. 63-68, July 1970.

T. Graettinger et al., “Evaluation and Time-Scaling of Trajectories forWheeled Mobile Robots,” ASME Journal of Dynamic Systems, Nov. 25, 1987.

Taylor, Benjamin R., “CMM accuracy measurements,” Quality Magazine, USA,1986. Upadhyay, T., et al., “Benefits on Integrating GPS and InertialNavigation,” pp. 1-13, June 1982.

Vaurus, J., “A Stimulation of an Imbedded Software System for GlobalPositioning System Navigation,” Proceedings of the 1985 WinterSimulation Conference, pp. 586-590, 1985. Vehicle Dynamics Terminology,SAE J670e, 1984.

VNIS '89 Conference Record, Sep. 11-13, 1989, Toronto, Canada, T. Saitoet al.

“Automobile Navigation System Using Beacon Information” pp. 139-145.

W. Nelson, “Continuous Steering-Function Control of Robot Carts,” AT&TBell Laboratories, April 1988.

W. Nelson, et al., “Local Path Control for an Autonomous Vehicle,” AT&TBell Laboratories, pp. 1504-1510, 1988.

W. Uttal, “Teleoperators,” Scientific American, pp. 124-129, December1989.

Wareby, Jan, “Intelligent Signaling: FAR & SS7”, Cellular Business, pp.58, 60 and 62, July 1990.

Wescon/87 Conference Record, vol. 31, 1987, (Los Angeles, US) M. T.Allison et al “The next generation navigation system”, pp. 941-947.

Y. Goto et al., “The CMU System for Mobile Robot Navigation,” TheRobotics Institutes, Carnegie-Mellon University, pp. 99-105, 1987.

Y. Kanayama et al., “A Locomotion Control Method for AutonomousVehicles,” pp. 1315-1317, 1988.

Y. Kanayama et al., “Smooth Local Path-Planning for AutonomousVehicles,” Center for Robotic Systems and Microelectronics, Universityof California at Santa Barbara, Mar. 7, 1988.

Yamada et al “GPS Navigator,” Japanese Radio Technical Bulletin No. 24,1986.

SUMMARY OF THE INVENTION

The present invention provides a mobile telecommunications device havinga position detector, which may be absolute, relative or other type, amemory for storing events in conjunction with locations, and atransmitter or receiver for communicating information stored or to bestored in the memory.

The aforementioned references, each incorporated by reference, relate tomethods and apparatus which may be used as part of, or in conjunctionwith the present invention. Therefore, it is understood that the presentinvention may integrate other systems, or be integrated in othersystems, having complementary, synergistic or related in some way. Forexample, common sensors, antennas, processors, memory, communicationshardware, subsystems and the like may provide a basis for combination,even if the functions are separate.

The position detector is preferably a GPS or combined GPS-GLONASSreceiver, although a cellular telephone position detection system (e.g.,Enhanced 911 type system) may also be employed. According to aspects ofthe present invention, a positional accuracy tolerance of 100 up to 1000meters may be acceptable, achievable with either type system. However,for such purposes as pothole reporting, positional accuracies of 1 to 3meters are preferred. These may be obtained through a combination oftechniques, and therefore the inherent accuracy of any one techniqueneed not meet the overall system requirement.

The position detector may also be linked to a mapping system andpossibly a dead reckoning system, in order to pinpoint a position with ageographic landmark. Thus, while precise absolute coordinatemeasurements of position may be used, it may also be possible to obtainuseful data at reduced cost by applying certain presumptions toavailable data. In an automotive system, steering angle, compassdirection, and wheel revolution information may be available, therebygiving a rough indication of position from a known starting point. Whenthis information is applied to a mapping system, a relatively preciseposition may be estimated. Therefore, the required precision of anotherpositioning system used in conjunction need not be high, in order toprovide high reliability position information. For example, where it isdesired to map potholes, positional accuracy of 10 cm may be desired,far more precise than might be available from a normal GPS receivermounted in a moving automobile. However, when combined with other data,location and identification of such events is possible. Further, whilethe system may include or tolerate inaccuracies, it is generally desiredthat the system have high precision, as compensation for inaccuraciesmay be applied.

The system provides a memory for storing events and respectivelocations. Preferably, further information is also stored, such as atime of the event, its character or nature, and other quantitative orqualitative aspects of the information or its source and/or conditionsof acquisition. This memory may be a solid state memory or module,rotating magnetic and/or optical memory devices, or other known types ofmemory.

The events to be stored may be detected locally, such as through adetector for radar and/or laser emission source, radio scanner, trafficor road conditions (mechanical vehicle sensors, visual and/or infraredimaging, radar or LIDAR analysis, acoustic sensors, or the like), placesof interest which may be selectively identified, itinerary stops, and/orfixed locations. The events may also be provided by a remotetransmitter, with no local event detection. Therefore, while means foridentifying events having associated locations is a part of the systemas a whole, such means need not be included in every apparatus embodyingthe invention.

Radar detectors typically are employed to detect operating emitters of X(10.5 GHz), K (25 GHz) and Ka (35 GHz) radar emissions from trafficcontrol devices or law enforcement personnel for detecting vehicle speedby the Doppler effect. These systems typically operate assuperheterodyne receivers which sweep one or more bands, and detect awave having an energy significantly above background. As such, thesetypes of devices are subject to numerous sources of interference,accidental, intentional, and incidental. A known system, Safety WarningSystem (SWS) licensed by Safety Warning System L.C., Englewood Fla.,makes use of such radar detectors to specifically warn motorists ofidentified road hazards. In this case, one of a set of particularsignals is modulated within a radar band by a transmitter operated nearthe roadway. The receiver decodes the transmission and warns the driverof the hazard.

LIDAR devices emit an infrared laser signal, which is then reflected offa moving vehicle and analyzed for delay, which relates to distance.Through successive measurements, a sped can be calculated. A LIDARdetector therefore seeks to detect the characteristic pulsatile infraredenergy.

Police radios employ certain restricted frequencies, and in some cases,police vehicles continuously transmit a signal. While certain lawsrestrict interception of messages sent on police bands, it is believedthat the mere detection and localization of a carrier wave is not andmay not be legally restricted. These radios tend to operate below 800MHz, and thus a receiver may employ standard radio technologies.

Potholes and other road obstructions and defects have twocharacteristics. First, they adversely affect vehicles which encounterthem. Second, they often cause a secondary effect of motorists seekingto avoid a direct encounter or damage, by slowing or executing anevasive maneuver. These obstructions may therefore be detected in threeways; first, by analyzing the suspension of the vehicle for unusualshocks indicative of such vents; second, by analyzing speed and steeringpatterns of the subject vehicle and possibly surrounding vehicles; andthird, by a visual, ultrasonic, or other direct sensor for detecting thepothole or other obstruction. Such direct sensors are known; however,their effectiveness is limited, and therefore an advance mapping of suchpotholes and other road obstructions greatly facilitates avoidingvehicle damage and executing unsafe or emergency evasive maneuvers. Anadvance mapping may also be useful in remediating such road hazards, aswell.

Traffic jams occur for a variety of reasons. Typically, the road carriestraffic above a threshold, and for some reason the normal traffic flowpatterns are disrupted. Therefore, there is a dramatic slowdown in theaverage vehicle speed, and a reduced throughput. Because of the reducedthroughput, even after the cause of the disruption has abated, theroadways may take minutes to hours to return to normal. Therefore, it istypically desired to have advance warnings of disruptions, which includeaccidents, icing, rain, sun glare, lane closures, road debris, policeaction, exits and entrances, and the like, in order to allow the driverto avoid the involved region or plan accordingly. Abnormal trafficpatterns may be detected by comparing a vehicle speed to the speed limitor a historical average speed, by a visual evaluation of trafficconditions, or by broadcast road advisories. High traffic conditions areassociated with braking of traffic, which in turn results indeceleration and the illumination of brake lights. Brake lights may bedetermined by both the specific level of illumination and the centerbrake light, which is not normally illuminated. Deceleration may bedetected by an optical, radar or LIDAR sensor for detecting the speedand/or acceleration state of nearby vehicles.

While a preferred embodiment of the present invention employs one ormore sensors, broadcast advisories, including those from systemsaccording to or compatible with the present invention, provide avaluable source of information relating to road conditions andinformation of interest at a particular location. Therefore, the sensorsneed not form a part of the core system. Further, some or all of therequired sensors may be integrated with the vehicle electronics(“vetronics”), and therefore the sensors may be provided separately oras options. It is therefore an aspect of an embodiment of the inventionto integrate the transceiver, and event database into a vetronicssystem, preferably using a digital vetronics data bus to communicatewith existing systems, such as speed sensors, antilock brake sensors,cruise control, automatic traction system, suspension, engine,transmission, and other vehicle systems.

The radio used for the communications subsystem can be radio frequencyAM, FM, spread spectrum, microwave, light (infrared, visible, UV) orlaser or maser beam (millimeter wave, infrared, visible), or for shortdistance communications, acoustic or other communications may beemployed. The system preferably employs an intelligent transportationsystem (ITS) or Industrial, Scientific and Medical (ISM) allocated band,such as the 915 MHz, 2.4 MHz or 5.8 GHz band. (The 2.350-2.450 GHz bandcorresponds to the emission of microwave ovens, and thus the bandsuffers from potentially significant interference). The 24.125 GHz band,corresponding to K-band police radar, may also be available; however,transmit power in this band is restricted, e.g., less than about 9 mW.The signal may be transmitted through free space or in paths includingfiber optics, waveguides, cables or the like. The communication may beshort or medium range omnidirectional, line of sight, reflected(optical, radio frequency, retroreflector designs), satellite, secure ornon-secure, or other modes of communications between two points, thatthe application or state-of-the-art may allow. The particularcommunications methodology is not critical to the invention, although apreferred embodiment employs a spread spectrum microwave transmission.

A number of Dedicated Short Range Communications (DSRC) systems havebeen proposed or implemented in order to provide communications betweenvehicles and roadside systems. These DSRC systems traditionally operatein the 900 MHz band for toll collection, while the FCC has recently madeavailable 75 MHz in the 5.850-5.925 GHz range for such purposes, on aco-primary basis with microwave communications, satellite uplinks,government radar, and other uses. However, spectrum is also available inthe so-called U-NII band, which encompasses 5.15-5.25 GHz (indoors, 50mW) and 5.25-5.35 (outdoors, 250 mW). At such frequencies, the preferredsemiconductor technology for the radio-frequency circuits is SiliconGermanium, available as a biCMOS heterojunction bipolar transistorprocess from IBM (CommQuest Technologies Division). Gallium Arsenideprocesses may also operate in this band. Silicon processes are preferredin the 900 MHz band and below.

A Japanese ITS (“ETC”) proposal provides a 5.8 GHz full duplexinterrogation system with a half duplex transponder, operating at about1 megabit per second transmission rates.

It is noted that the present technology has the capability forstreamlining transportation systems, by communicating traffic conditionsalmost immediately and quickly allowing decisions to be made by driversto minimize congestion and avoid unnecessary slowdowns. A particularresult of the implementation of this technology will be a reduction invehicular air pollution, as a result of reduced traffic jams and otherinefficient driving patterns. To further the environmental protectionaspect of the invention, integration of the database with cruise controland driver information systems may reduce inefficient vehicle speedfluctuations, by communicating to the driver or controlling the vehicleat an efficient speed. As a part of this system, therefore, adaptivespeed limits and intelligent traffic flow control devices may beprovided. For example, there is no need for fixed time traffic lights ifthe intersection is monitored for actual traffic conditions. Byproviding intervehicle communications and identification, such anintelligent system is easier to implement Likewise, the 55 miles perhour speed limit that was initially presented in light of the “oilcrisis” in the 1970's, and parts of which persist today even in light ofrelatively low petroleum pricing and evidence that the alleged secondaryhealth and safety benefit is marginal or non-existent, may be eliminatedin favor of a system which employs intelligence to optimize the trafficflow patterns based on actual existing conditions, rather than a staticset of rules which are applied universally and without intelligence.

The communications device may be a transmitter, receiver or transceiver,transmitting event information, storing received event information, orexchanging event information, respectively. Thus, while the system as awhole typically involves a propagation of event information betweenremote databases, each system embodying the invention need not performall functions.

In a retroreflector design system, signal to noise ratio is improved byspatial specificity, and typically coherent detection. An interrogationsignal is emitted, which is modulated and redirected back toward itssource, within a relatively wide range, by a receiver. Thus, while thereceiver may be “passive”, the return signal has a relatively highamplitude (as compared to non-retroreflective designs under comparableconditions) and the interrogator can spatially discriminate andcoherently detect the return signal. Both optical and RF retroreflectorsystems exist.

In a preferred embodiment, the communications device employs anunlicensed band, such as 900 MHz (902-928 MHz), FRS, 49 MHz, 27 MHz,2.4-2.5 GHz, 5.4 GHz, 5.8 GHz, etc. Further, in order to provide noiseimmunity and band capacity, spread spectrum RF techniques are preferred.

In one embodiment, communications devices are installed in automobiles.Mobile GPS receivers in the vehicles provide location information to thecommunications devices. These GPS receivers may be integral or separatefrom the communications devices. Event detectors, such as police radarand laser (LIDAR) speed detectors, traffic and weather conditiondetectors, road hazard detectors (pot holes, debris, accidents, ice, mudand rock slides, drunk drivers, etc.), traffic speed detectors(speedometer reading, sensors for detecting speed of other vehicles),speed limits, checkpoints, toll booths, etc., may be provided as inputsto the system, or appropriate sensors integrated therein. The system mayalso serve as a beacon to good Samaritans, emergency workers and othermotorists in the event of accident, disablement, or other status of thehost vehicle.

It is noted that at frequencies above about 800 MHz, the transmittersignal may be used as a part of a traffic radar system. Therefore, thetransmitted signal may serve both as a communications stream and asensor emission.

Functions similar to those of the Cadillac (GM) On-Star system may alsobe implemented, as well as alarm and security systems, garage dooropening and “smart home” integration.

The memory stores information describing the event as well as thelocation of the event. Preferably, the memory is not organized as amatrix of memory addresses corresponding to locations, e.g., a “map”,but rather in a record format having explicitly describing the event andlocation, making storage of the sparse matrix more efficient andfacilitating indexing and sorting on various aspects of each datarecord. Additional information, such as the time of the event,importance of the event, expiration time of the event, source andreliability of the event information, and commercial and/or advertisinginformation associated with the event may be stored. The information inthe memory is processed to provide a useful output, which may be asimple alphanumeric, voice (audible) or graphic output or thetelecommunications system. In any case, the output is preferablypresented in a sorted order according to pertinence, which is acombination of the abstract importance of the event and proximity, with“proximity” weighted higher than “importance”. Once a communication oroutput cycle is initiated, it may continue until the entire memory isoutput, or include merely output a portion of the contents.

In outputting information directly to a human user, thresholds arepreferably applied to limit output to events which are of immediateconsequence and apparent importance. For example, if the communicationsdevice is installed in a vehicle, and the information in the memoryindicates that a pothole, highway obstruction, or police radar “trap” isahead, the user is informed. Events in the opposite direction (asdetermined by a path or velocity record extracted from the positiondetector) are not output, nor are such events far away. On the otherhand, events such as road icing, flooding, or the like, are oftenapplicable to all nearby motorists, and are output regardless ofdirection of travel, unless another communications device with eventdetector indicates that the event would not affect the localcommunications device or the vehicle in which it is installed.

The system preferably ages event data intelligently, allowing certaintypes of events to expire or decrease in importance. A traffic accidentevent more than 12 hours old is likely stale, and therefore would not beoutput, and preferably is purged; however, locations which are the siteof multiple accidents may be tagged as hazardous, and the hazard eventoutput to the user as appropriate.

A temporal analysis may also be applied to the event data, and thereforediurnal variations and the like accounted for. Examples of this type ofdata include rush hour traffic, sun glare (adjusted for season, etc.),vacation routes, and the like.

Thus, user outputs are provided based on proximity, importance, andoptionally other factors, such as direction, speed (over or under speedlimit), time-of-day, date or season (e.g., sun glare), freshness ofevent recordation, and the like.

In communicating data to another communications device, typically it isdesired to transmit (or exchange) all of the memory or all of a “public”portion of the memory, with the received information sorted andprocessed by the receiving unit and relevant information persistentlystored in the memory. After exchange, conflicts may be resolved by afurther exchange of information. An error detection and correction (EDC)protocol may be employed, to assure accurate data transmission.

Since the communication bandwidth is necessarily limited, and thecommunications channels subject to noise and crowding, it is oftenimportant to prioritize transmissions. It is noted that, without acomplete communication of the memory, it is difficult to determine whichevents a communications partner is aware of, so that an initialcommunication may include an identification of the partners as well asrecent encounters with other partners, to eliminate redundantcommunications, where possible. Vehicles traveling in the same directionwill often be in close proximity longer than vehicles traveling inopposite directions. Further, the information of relevance to a vehicletraveling in the same direction will differ from the information ofrelevance to a vehicle traveling in the opposite direction. Thus, inaddition to an identification of the communications device, the recentpath and proposed path and velocity should also be exchanged. Based onthis information, the data is prioritized and sorted, formatted andtransmitted. Since the communications channel will likely vary independence on distance between partners, the communications protocol maybe adaptive, providing increased data rate with decreasing distance, upto the channel capacity. Further, when the vehicles are relativelyclose, a line-of-sight communications scheme may be implemented, such asinfrared (e.g., IRdA), while at larger distances (and/or for alldistances) a spread spectrum 915 MHz, 2.4 GHz or 5.825 GHz RFcommunications scheme implemented.

Where multiple communications devices are present within a commoncommunications region, these may be pooled, allowing transmissions fromone transmitter to many receivers. In addition, within a band, multiplechannels may be allocated, allowing multiple communications sessions. Inthis case, a single arbitration and control channel is provided toidentify communications devices and communications parameters.Preferably, a communications device has the capability to monitormultiple channels simultaneously, and optionally to transmit on multiplechannels simultaneously, where channel congestion is low. The channelsare typically frequency division. Where such frequency division channelsare defined, communications may be facilitated by so-called “repeaters”,which may itself be a mobile transceiver according to the presentinvention. Preferably, such a repeater unit itself monitors the datastream, and may even process the data stream based on its internalparameters before passing it on.

In order to assure data integrity and optimize data bandwidth, bothforward and retrospective error correction are applied. Data ispreferably packetized, with each packet including error detection andcorrection information. Successful receipt of each packet isacknowledged on a reverse channel, optionally interspersed withcorresponding data packets traveling in the reverse direction (e.g.,full duplex communications). Where the data error rate (raw orcorrected) is unacceptably high, one or more “fallback” modes may beimplemented, such as reduced data rates, more fault tolerant modulationschemes, and extended error correction and detection codes. Transmitterpower may also be modulated within acceptable limits.

A central repository of event data may be provided, such as on theInternet or an on-line database. In this case, event information may beadministered remotely, and local storage minimized or eliminated.Communications with the central database may be conducted by cellulartelephone, cellular data packet devices (CDPD), PCS, GSM, satellite(Iridium™, etc.) or in other communications bands and othercommunications schemes.

Alternately, or in addition, the communications device may include atelephone modem (digital to analog modulator-demodulator) for exchangingevent information over telephone communications lines. The deviceaccording to the present invention may either be plugged into a walljack, use acoustic coupling (advantageous, for example, forpay-telephones) or communicate wirelessly with a base unit, such aswhile parked in a garage or service station. Where primary eventinformation storage is remote from the device, preferably local storageis based on an itinerary (route) and frequently traveled areas, withless frequently traveled and not prospectively traveled routes storedremotely. This allows consolidated update of memory by a large number ofsources, with statistical error detection and correction of errant eventinformation. The itinerary information may be programmed in conjunctionwith the GPS system and mapping software.

According to one embodiment of the invention, the functions areintegrated into a single device, including police radar and LIDARdetectors, user output, memory, central processor, GPS receiver and RFtransceiver. Accessory inputs and outputs may also be provided,including means for alphanumeric, graphic (still or motion) or voicemessage communication between communications devices. Event informationis communicated as packets including full event information as well aserror correction and detection codes. The packet size is preferablylarge enough to minimize the impact of communications protocol overheadwhile small enough to minimize the efficiency loss resulting from fullpacket retransmissions. For example, a control channel is provided with256 bit packets, while a set of regular communications channels isprovided with 512 bit packets. Event information may span multiplepackets or be consolidated within packets. The data is preferablycompressed using a dictionary lookup, run length encoding, and/ormodel-based vector quantization method. Thus, since transceivers willtypically be within 2000 meters from each other, relative position maybe relayed in an offset format, with a grid size based on GPS precisionand required accuracy, e.g., about 50-100 meters. The encoding may beadaptive, based, for example, on stored map information, withinformation representation density highest on traveled routes and lowerin desolate areas. Thus, a sort of differential-corrected positionalcoding may be established between units.

By integrating functions, efficiencies are achieved. Thus, a singlecentral processor, memory, program store and user interface will sufficefor all functions. Further, the power supply and housing are alsoconsolidated. While GPS and telecommunication antennas will be distinct,other portions of the system may also be integrated. In a deviceintended for vehicular applications, the GPS and other functions may beavailable to other vehicular systems, or the required data received fromother systems. For example, the Cadillac (GM) On-Star system mightsupply GPS signals to the communications device according to the presentinvention, or vice versa.

Communication between communications devices may also employ thecellular telephone network, for example utilizing excess capacity in alocal or regional communication mode rather than linked to the publicswitched telecommunications network (PSTN). Thus, the system may includeor encompass a typical cellular (AMPS, IS-136, IS-95, CDPD, PCS and/orGSM) type telecommunications device, or link to an externaltelecommunications device.

Even where the cellular telephony infrastructure is not involved, mobilehardware may be reused for the present invention. For example, theoutput of a mobile cellular transceiver may be “upconverted” to, forexample, 900 MHz or 2.4 GHz, and retransmitted. While this is somewhatinefficient in terms of power and complexity, it allows use of existingcellular devices (with software reprogramming and data interfacing) inconjunction with a relatively simple upconversion transmitter.

According to the present invention, messages are passed between anetwork of free roving devices. In order to maintain network integrity,spurious data must be excluded. Thus, in order to prevent a “hacker” ormiscreant (e.g., overzealous police official) from intentionallycontaminating the dispersed database, or an innocent person fromtransmitting corrupted data, the ultimate source of event data isrecorded. When corrupt or erroneous data is identified, the source isalso identified. The corrupting source is then transmitted or identifiedto the central database, whereupon, units in the field may be programmedto ignore the corrupt unit, or to identify its location as a possibleevent to be aware of.

Preferably, data is transmitted digitally, and may be encrypted.Encryption codes may be of a public-key/private key variety, with keylookup (e.g., by a cellular telephony or CDPD-type arrangement to acentral database) either before each data exchange, or on a global basiswith published updates. In fact, corrupt or unauthorized units may bedeactivated by normal and authorized units within the network, thusinhibiting “hacking” of the network. Thus, a subscription based systemis supported.

Techniques corresponding to the Firewire (IEEE 1394) copy protectionscheme may be implemented, and indeed the system according to thepresent invention may implement or incorporate the IEEE 1394 interfacestandard. While the event database is generally not intended to becopy-protected, the IEEE 1394 key management scheme may be useful forimplementing subscription schemes and for preventing tampering.

One way to subsidize a subscription-based system is through advertisingrevenue. Therefore, the “events” may also include messages targeted toparticular users, either by location, demographics, origin, time, orother factors. Thus, a motel or restaurant might solicit customers whoare close by (especially in the evening), or set up transponders alonghighways at desired locations. Travelers would then receive messagesappropriate to time and place. While the user of the system according tothe present invention will typically be a frequent motorist or affluent,the system may also provide demographic codes, which allow a customizedresponse to each unit. Since demographic information is personal, andmay indicate traveler vulnerability, this information is preferably nottransmitted as an open message and is preferably not decodable byunauthorized persons. In fact, the demographic codes may be employed tofilter received information, rather than to broadcast interests.

Commercial messages may be stored in memory, and therefore need not bedisplayed immediately upon receipt. Further, such information may beprovided on a so-called “smart card” or PC Card device, with messagestriggered by location, perceived events, time and/or other factors. Inturn, the presentation of commercial messages may be stored forverification by an auditing agency, thus allowing accounting foradvertising fees on an “impression” basis.

The communications device may also receive data through broadcasts, suchas using FM sidebands, paging channels, satellite transmission and thelike. Thus, locationally or temporally distant information need not betransmitted between mobile units.

While low power or micropower design is desirable, in an automobileenvironment, typically sufficient power is continuously available tosupport sophisticated and/or power hungry electronic devices; thus,significant design freedom is provided to implement the presentinvention using available technologies.

These and other objects will become clear through a review of thedrawings and detailed description of the preferred embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

The drawings show:

FIG. 1 is a block diagram of a preferred embodiment of a communicationssystem according to the present invention;

FIG. 2 is a schematic diagram showing the prioritization scheme; and

FIG. 3 is a block diagram representing a message format.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 shows a block diagram of an communications device embodiment ofthe present invention. The mobile communications device 1 includes, asnecessary elements, a location sensing system 2, producing a locationoutput 3; a memory 4, storing a set of locations and associated events;a telecommunications subsystem 5, communicating event and locationinformation between a remote system and the memory 4; and a processor 6,processing the location output in conjunction with the stored locationsand associated events in the memory 4, to determine a priority thereof.

The location sensing system 2 comprises a known GPS receiver, whichproduces data that is analyzed by the processor 6. In an alternateembodiment, the GPS receiver includes its own processor and outputscoordinate positions, e.g., Cartesian coordinates, latitude andlongitude, to the communications device processor 6, e.g., through aserial port or data bus, such as PC card, Universal serial Bus (USB),Firewire (IEEE 1394), peripheral connect interface (PCI), or other bus,such as that present within an automobile for communication of signalsbetween subsystems. The location sensing system may also determine aposition based on the GLONASS system, LORAN, inertial reference,cellular base stations 10′, 10″, triangulation with fixed radio sources,such as FM radio and television stations, environmental markers and/ortransponders, or the like.

The communications subsystem 5 is a 900 MHz digital spread spectrumradio transceiver 12, operating unlicensed according to FCC regulationsfor this type of equipment. The system may alternately or additionallycommunicate in other unlicensed bands, such as 27 MHz, 49 MHz, FRS band,2.4-2.5 GHz, 5.4 GHz, 5.8 GHz using various known modulation schemes anddata communication protocols. Further, licensed radio bands may also beused, including FM radio sidebands (88-108 MHz), television PRO channel,cellular telephony channels, DECT, PCS and GSM channels, and the like.Likewise, satellite systems 16, 17 may be used to communicate with themobile communications device 1. Thus, for example, instead of directcommunication between mobile units, the existing cellular telephony 10′,10″ infrastructure may be used to provide intercell, local, and/orregional communications between units, controlled by cellular telephoneswitching processors 11′, 11″. These communications may be given a lowerpriority than voice communications on the cellular telephone network,and therefore may use otherwise excess bandwidth, thus allowing reducedcosts and reduced user fees or subscription rates. Further, this schemeallows use of existing cellular telephones 14, as or instead of anintegrated communications subsystem operating according to a differentstandard. For example, cellular telephones may be present in the vehiclefor voice communications purposes, and therefore simultaneously with asystem according to the present invention. In this case, thecommunications device need only have a data communications transceiverfor interfacing with a cellular communication device, e.g., AMPS, IS-95,IS-136, CDPD, DECT, GSM and PCS, and need not integrate the radiofrequency communication device components. In a variant embodiment, acellular-type telephone is controlled to operate outside the (AMPS)cellular telephone channels, in the 900 MHz band. It is noted thatexisting cellar communications system do not support high bandwidth datacommunications when using a single channel. On the other hand, themodifications to a digital cellular communications device to allocate afull time division multiplexed (TDM) channel to as single transceiverare theoretically simple, and allow relatively high data rates. Thus,slightly modified transceivers may be employed. Such modifiedtransceivers may also be used for other high bandwidth mobilerequirements, such as mobile video-conferencing, and the like.

The memory 4 may be of any standard type, for example, static randomaccess memory, dynamic random access memory, ferroelectric memory,magnetic domain memory (e.g., diskette, hard disk), non-volatilesemiconductor memory (e.g., UV-EPROM, EEPROM, Flash, non-standardelectrically erasable programmable non-volatile memory), opticallyreadable memory (e.g., R-CDROM, RW-CDROM, R-DVD, etc.),scanning/tunneling micromechanical memory systems, and the like.Preferably, common memory devices, such as 72 or 168 pin dynamic RAMsingle inline memory modules (SIMMs) are employed, at least for avolatile portion of the memory, allowing simple upgrades and industrystandard compatibility.

While the preferred embodiment includes a radio frequency transceiverfor transmitting event data and receiving event data, embodiments arealso possible which either transmit or receive the relevant data, butnot both. For example, regulations may limit certain transmissions orrelevant event sensors, e.g., radar detectors in trucks. In these cases,a receive only embodiment may be appropriate. Further, while radiofrequency communications are preferred, due to their range, datacapacity and availability, optical communications systems 13, e.g.,infrared LED's and laser diodes, acoustic communication 15, passivebackscatter communications (employing an RF transceiver such as thespread spectrum transceiver 12), and the like may also be employed inconjunction or in substitution of a radio frequency system. Opticalcommunication systems 13 may employ various detectors, including opticalhomodyne detectors, or other coherent optical detectors, or other typesof optical sensors, such as PIDs, CCDs, silicon photodiodes, and thelike.

Under some circumstances, a wired link between units may be appropriate.For example, a central database 20 may provide consolidated and reliabledata. The relevant portion of the database 20 may be downloaded bytelephone through a modem 21, either through a physical connection 23(e.g., RJ-11 or RJ-12 jack) or through an acoustic coupler 22, throughthe public switched telephone network, Internet or other network 24, toa database server 25. The memory 4 of the mobile unit may also beuploaded to the central database 20, after processing by the databaseserver 25, during the same connection or session.

Thus, according to the present invention, the public switched telephonenetwork 24 may be involved both during intermittent mass datacommunications with a central database 20, and also using, for example,cellular telephony 14, for the normal operation of the system (e.g.,communications between mobile units).

The processor 6 analyzes the information stored in memory 4 to provide aprioritized output. Thus, the memory may store information relating to arelatively large number of events, without overwhelming the capacity ofa human user or communications partner. Priority may be based on anumber of factors, including proximity of a stored location to a sensedlocation or a spatial-temporal proximity of a stored location to a lociof an itinerary 101, a prospective conjunction 102 of a sensed locationwith a stored location, a type of event 103, a type of event and asensed condition associated with the mobile communications device 104,or other factors or a combination of factors. Neural networks, fuzzylogic and/or traditional logic paradigms may also be employed toprioritize the outputs. These logical paradigms are provided in knownmanner, and, especially in the case of neural network-based systems, atraining aspect may be supplied with the system to allow it to adapt tothe preferences and capabilities of the user. Thus, for a human user,events which are forthcoming and important are output, while past eventsand those in the distant future, if at all, are low priority. On theother hand, for communications with other devices, the prioritization isprimarily in consideration of the fact that the communication betweenunits may be only short lived; therefore, the data is communicated inorder to priority, preferably of the recipient device. In an adaptivedevice, if the user believes that the information from the device isinappropriate, a simple input is provided, which is later analyzed toalter the information presentation algorithm. Likewise, if aninformation alert retrospectively turns out to be erroneous is apredictable manner, i.e., relating to a route not taken, the system mayinternally adjust the algorithm without user input.

In order to sort the priorities, the intended recipient may, forexample, identify itself 201 and communicate its location 202 anditinerary or intended or prospective path 205. High priority messages204 and various codes 203 may be interspersed through the communicationstring. The transmitting unit then outputs data 206 in order of thecomputed or predicted importance of the event and the time before therecipient encounters the event. Static events, such as fixed locationradar emission sources, which may, for example, indicate a source forinterference with a radar detector, or a speed detection/control device,may be transmitted as well.

Therefore, it is noted that the present invention provides a means formapping events and for analyzing their significance. Thus, thisembodiment does not merely rely on processed sensor outputs to supplyinformation to the user; rather, sensor outputs may be filtered based onpast experience with the particular location in question. If aparticular user does not have direct experience with a location, thenthe experience of others at that location may be substituted or combinedto improve analysis of the sensor signal. Therefore, the signal analysisfrom the sensor need not be subjected to a relatively high threshold toavoid false alarms. A low threshold is acceptable because otherinformation is employed to determine the nature of the physical elementswhich give rise to the event and sensor activation.

It is noted that, in the case of “false alarms”, the response of theunit is to detect the event, e.g., radar signal, correlate it with astored “false alarm” event, and suppress an alarm or modify the alarmsignal. Thus, information stored in memory and/or transmitted betweenunits, may signify an important alarm or a suppression of an erroneousalarm. In this context is apparent that the integrity of the databasestructure, especially from corruption by the very sources of alarmswhich are intended to be detected, is important. To the extent that theenvironment responds to the existence and deployment of the systemaccording to the present invention, for example by detectingtransmissions between units to identify and locate units, and therebyalter the nature of an event to be detected, the present system may alsobe adaptive, in terms of its function and signature spectral patterns.In one aspect, the system may employ a so-called “FLASH” upgradablememory, which controls system, operation. Therefore, periodically, thesystem operation may be altered. The communications may selectivelyoccur on a plurality of bands, using a plurality of protocols. Thus, forexample, the system may have tri-band capability, e.g., 900 MHz, 2.4 GHzand 5.8 GHz. The mapping feature of the present invention may also beused to identify the locations of such monitoring sites. The system mayalso mask its transmissions as other, more common types of transmissionsor environmental sources of emissions. A direct sequence spread spectrumtechnique maybe employed which is difficult to detect without knowingthe spread spectrum sequence seed. Of course, an aspect of the presentinvention is open communications, which as a matter of course are notsecurely encrypted and which would identify the transponder and itslocation. This problem may be addressed, in part, relying on laws whichprevent unauthorized eavesdropping and unauthorized interception anddecryption of communications, unauthorized “copying” of copyright worksand defeating of copy protection schemes thereof, control overavailability of authorized transceivers, and patent protection of thedesign and implementation.

Thus, in a preferred design, all communications are direct sequencespread spectrum over a wide band, with medium to high security codes,e.g., 10 bits or greater length chip sequence and 12 bits or greaterdata encryption, and more preferably 16 bit or greater chip sequence and16 bit or greater data encryption. The chip sequence of the control andarbitration channel, which must be available to all compatible units,may be adaptive or changing, for example following a formula based ontime, location, and/or an arbitrary authorization code provided with asubscription update. Further, the chip sequence may vary based onselective availability (SA) deviancies in GPS data, or based on theidentity of satellites in view of the receiver. While such informationmight be available to “pirates”, miscreants, hackers and scofflaws, thealgorithm for generating the chip sequence might be held asconfidential, and thus the system unusable without specificauthorization and incompatible with equipment without such algorithm.Such systems employing secure encryption with open access have beenemployed in satellite television (General Instrument VideoCipher II) andthe like. It is noted that, in order to mask a message in a spreadspectrum signal, multiple active channels may be employed, one or moreof which transmits the desired data and the remainder transmitting noiseor masking data.

Employing 2.4 or 5.8 GHz communications bands, data rates of 10 megabitsper second (MBPS) are possible, although lower rates, such as 0.5-1.0MBPS may be preferred to reduce loss due to interference or adversecommunications conditions and maintain availability of simultaneouscommunications on multiple channels within the band in a smallgeographic area.

Where mobile devices are traveling parallel and at similar speeds, orboth are stopped, an extended communications session may be initiated.In this case, the data prioritization will be weighted to completelyexchange a public portion of the database, although emphasis will stillbe placed on immediately forthcoming events, if anticipated. On theother hand, where computed or user-input trajectories indicate a likelybrief encounter, the immediate past events are weighted most heavily.

In order to analyze temporal relevance, the memory 4 preferably storesan event identifier 301, a location 302, a time of detection of an event303, a source of the event information 304, an encoding for a likelyexpiration of the event 305, a reliability indicator for the event 306,and possibly a message associated with the event 307 including otherinformation. These data fields may each be transmitted or received todescribe the event, or selectively transmitted based on the nature ofthe event or an initial exchange between units specifying theinformation which will be communicated.

For example, in a radar detector embodiment, mobile police radar “traps”are often relocated, so that a particular location of one event shouldnot be perpetuated beyond its anticipated or actual relevance. In thiscase, expirations may be stored, or calculated based on a “type” ofevent according to a set of rules. False alarms, due to securitysystems, traffic control and monitoring systems, and the like, may alsobe recorded, to increase the reliability any warnings provided.

Likewise, traffic jams often resolve after minutes or hours, and, whilecertain road regions may be prone to traffic jams, especially at certainhours of the day and/or days of the week, abnormal condition informationshould not persist indefinitely.

The preferred embodiment according to the present invention provides anevent detector, which, in turn is preferably a police radar 18 and LIDAR19 detector. Other detected events may include speed of vehicle, trafficconditions, weather conditions, road conditions, road debris orpotholes, site designation, sources of radio signals or interference orfalse alarms for other event detectors, and particular vehicles, such asdrunk drivers or unmarked police cars (possibly by manual event input).The event detector may include, for example, a sensor, such as a camera26, which may analyze traffic control indicia (such as speed limits,cautions, traffic lights). The event may also include a commercialmessage or advertisement, received, for example from a fixed antennabeside a road, which, for example, is stored as the message 307. Such acommercial message 307 may be presented immediately or stored for futureoutput. The received message, whether commercial or not, may be a staticor motion graphic image, text or sound message. The user output of thesystem 27 may thus be visual, such as a graphic or alphanumeric (text)display, indicator lights or LED's 28, audible alerts or spoken voicethrough an audio transducer 29.

The camera is, for example, a color, monochrome or infrared chargecoupled device (CCD) or complementary metal oxide silicon field effecttransistor (CMOS) imager, having resolution of CIF (common interchangeformat), QCIF (quarter common interchange format), NTSC (nationaltelevision standards committee), PAL (phase-alternate line), or otherstandard, and preferably images using NTSC format and transmits, if atall, as QCIF. Image communication may be, for example H.261 or H.263,using H.324+ (using mobile communications extensions) or H.323 protocol.The imager may also be incorporated as part of a mobilevideoconferencing system, although a dual imager system (one for imagingpersons and the other for imaging road conditions) may be implemented.Other ITU standards, e.g., T.120, may be employed for datacommunications, although the particular nature of the datacommunications channel(s) may compel other communications protocols.

In order to maintain the integrity of the database stored in memory 4,20, it may be useful to store the originator of a record, i.e., itssource 304. Thus, if event information from that origin is deemedunreliable, all records from that source may be purged, and futuremessages ignored or “flagged”. As stated above, even the proximity of anunreliable or modified unit may be detrimental to system operation.Therefore, where the location of such a unit is known, other units inproximity may enter into a silent mode. Further, normal units maytransmit a “kill” message to the unreliable unit, causing it to ceasefunctioning (at least in a transmit mode) until the problem is rectifiedor the unit reauthorized.

The unit is preferably tamper-proof, for example, codes necessary forunit activation and operation are corrupted or erased if an enclosure tothe unit is opened. Thus, techniques such as employed in the GeneralInstrument VideoCipher II and disclosed in Kaish et al., U.S. Pat. No.4,494,114, may be employed.

The communications subsystem preferably employs an errorcorrection/error detection protocol, with forward error correction andconfirmation of received data packet. The scheme may be adaptive to thequality of the communication channel(s), with the packet length,encoding scheme, transmit power, bandwidth allocation, data rate andmodulation scheme varied in an adaptive scheme to optimize thecommunication between units. In many cases, units engaged incommunication will exchange information bidirectionally. In that case, afull duplex communication protocol is preferred; on the other hand,where communication is unidirectional, greater data communication ratesmay be achieved employing the available bandwidth and applying it to thesingle communication session.

In some instances, it may be desired to maintain privacy ofcommunications. In that case, two possibilities are available; spreadspectrum communications, preferably direct sequence spread spectrumcommunications is employed, to limit eavesdropping possibilities.Second, the data itself may be encrypted, using, for example, a DES,PGP, elliptic keys, or RSA type encryption scheme. Keys may be suppliedor exchanged in advance, negotiated between partners, or involve apublic key-private key encryption algorithm. For example, the spreadspectrum communications chip sequence may be based on an encrypted code.

In order to provide flexibility in financing the communications devices,the commercial messages 307 discussed above may be employed. Further, bycirculating authorization tokens or codes 203, a subscription servicemay be provided. Thus, in a simplest subscription scheme, thecommunications device has a timer function, which may be a simple clockor GPS referenced. The user must input an authorization codeperiodically in order for the device to continue operating. Thus,similarly to satellite television receivers and some addressable cabletelevision decoders, failure to provide the authorization code, whichmay be entered, e.g., by telephone communication or through a keypad 30,renders the device temporarily or permanently inoperative. In order toreduce the burden of reauthorizations, the authorization codes or tokensmay be passed through the communications “cloud” 24, so that devices 1,if used, will eventually receive the authorization data. Conversely, acode 203 may be circulated which specifically deactivates a certaindevice 1, for example for non-payment of the subscription fee or misuseof the device (e.g., in an attempt to corrupt other users databases).The authorization process is preferably integral to the core operationof the system, making bypassing authorization difficult.

Where a number of communications devices are in proximity, a multi-partycommunication session may be initiated. For example, the communicationssubsystem may have simultaneous multi-channel capability, allowing eachunit to transmit on a separate channel or use a shared channel. Wherethe number of channels or channel capacity is insufficient, units maytake turns transmitting event information on the same channel (e.g.,according to estimated priority), or time division multiplex (TDM) thechannel(s). Preferably, the communication scheme involves a number ofchannels within a band, e.g., 1 common control channel and 24 datacommunications channels. Since some communication sessions may berelatively short, e.g., limited to a few seconds, a data communicationschannel preferably has a maximum capacity of tens of kilobits per secondor higher. In some cases, hundreds of kilobits, or megabit rangebandwidths are achievable, especially with a small number of channels(e.g., one channel). Thus, for example, a DSSS spread spectrumtransceiver operating in the 2.5 GHz band might have a usable bandwidthof 10 megabits per second, even while sharing the same band with othertransceivers in close proximity. Where necessary, directional antennasor phased arrays may be employed to provide spatial discrimination.

The system preferably has advanced ability to detect channel conditions.Thus, where communications are interrupted by physical limitations inthe channel, the impairment to the communications channel is detectedand the communications session paused until the impairment abates. This,in turn, will allow other units, which might not be subject to theimpairment, to use the same channel during this interval. The channelimpairment may be detected by a feedback protocol between communicationspartners, or by means of symmetric antennas and communications systems,by which an impairment of a received signal may be presumed to affectthe transmitted signal as well. The latter requires a high degree ofstandardization of equipment design and installation for effectiveness.

It is particularly noted that, where the events to be detected and thecommunications subsystem operate in the same band, structures may beshared between the communications and event detection systems, but thisalso increases the possibilities for interference.

As one embodiment of the invention, the processor may be provided as astandard personal digital assistant (PDA) with a PC Card or PCMCIA slotfor receiving a standard GPS receiver module. The PDA, in turn hasmemory, which may include random access memory, flash memory, androtating magnetic memory (hard disk), for example. The PDA also includesa data communications port, which sends data to and controls thecommunications subsystem, which may be, for example, model interfacingwith, e.g., a cellular telephone or CDPD system. The PDA has aprocessing system which is capable of running applications written ingeneral purpose, high level languages such as C. The PDA may operateunder a standard operating system, such as Microsoft Windows CE, or aproprietary operating system. A software application written in a highlevel language can normally be ported to run in the PDA processingsystem. Thus, the basic elements of the hardware platform are allavailable without customization. In a preferred embodiment, an eventsensor is provided, such as a police radar and laser speed detectionequipment system (e.g., “radar detector”) is provided. This may employ amodified commercially available radar detector, to produce a serial datastream or parallel signal set. For example, radar detectors providing analphanumeric display often transmit data to the display controller bymeans of a serial data signal. This signal may be intercepted andinterfaced with a serial port or custom port of the PDA.

Optionally, the GPS Smart Antenna is “differential-ready” to applydifferential GPS (DGPS) error correction information to improve accuracyof a GPS determined location. The application program for the PDA may beprovided in a semiconductor memory cartridge or stored on hard disk.

The PDA 30 includes the processing system, including a microprocessor,memory, pre-coded program instructions and data stored in memory, amicroprocessor bus for addresses, data, and control, an interrupt busfor interrupt signals, and associated hardware, operates in aconventional manner to receive digital signals, process information, andissue digital signals. A user interface in the PDA includes a visualdisplay or audible output to present signals received from theprocessing system to a user, a user entry system to issue signals fromthe user to the processing system. The user interface may include one ormore push keys, toggle switches, proximity switches, trackballs,joysticks or pressure sensitive keys, a touch-sensitive display screen,microphones or a combination of any of the above used together or withother similar type user input methods. The PDA sends digital signalsrepresenting addresses, data, and commands to the memory device andreceives digital signals representing instructions and data from thememory. A PDA interface electrically connects the processing system to aGPS Smart Antenna. If the PDA and GPS are not integrated, a preferredinterface comprises a computer-standard low to medium speed serial datainterface, such as RS-232, RS-422, or USB, through a cabled interfacefor connection to the GPS Smart Antenna.

The GPS Smart Antenna system includes a GPS receiver antenna to receiveGPS satellite signals from GPS satellite transmitters, a GPS frequencydownconverter to downconvert the approximately 1.575 GHz frequency ofthe L1 GPS satellite signals to a lower frequency (LF) signal that issuitable for digital processing, and to issue the LF to a GPS processor.The GPS processor demodulates and decodes the LF signal and provideslocation information for at least one of (i) location of the GPSantenna, (ii), GPS satellite pseudoranges between the GPS satellites andthe GPS antenna, (iii) rate of change of location of the GPS antenna,(iv) heading of the GPS antenna, and (v) time to a GPS interface.Optionally, the GPS Smart Antenna and GPS processor aredifferential-ready. An optional input select switch, controlled by theGPS processor upon a request from the PDA, allows a single serialinterface to receive either a control signal from the PDA or a DGPSerror correction signal from an optional DGPS radiowave receiver.Alternately, a DGPS-type system may be coordinated between multiplemobile receivers, top provide high relative position accuracy, evenwhere the absolute position accuracy is low. Since the event positioncalculations are based on the relative position frame, the effect is toaccurately position the events with respect to the vehicle.

The user device may display, for example, map features according to acoordinate system such as latitude and longitude. The display may alsoinclude an indication of the location of the GPS receiver, an itinerary,proposed route, and indications of the location of various events. Bycorrelating the GPS with a stored map, the absolute location of thevehicle may be determined by map matching techniques. In accordance withthe present invention, these events are derived from the event detectoror the memory. Other communications devices may also be located on thedisplay.

The user entry system has both touchscreen keys and press keys in thepresent embodiment. With a touchscreen, a user enters a request bytouching a designated portion overlying a visual display with his finger(or soft pointer, such as a plastic pen). The touchscreen senses thetouch and causes a digital signal to be sent to the processing systemindicating where the touch was made. Switches such as rotary switches,toggle switches, or other switches can equally well be applied. Anadvantage of the touchscreen is that a label or a placement of thetouchscreen, and a corresponding function of the touchscreen, may bechanged by the computer controlling the display any number of timeswithout changing electrical or mechanical hardware. In the presentembodiment, zoom keys may be employed change scale and resolution of amap on the display. Zooming in decreases the scale, so that the map isviewed with greater resolution over a lesser area of the map. Zoomingout increases the scale, so that a greater area of the map is viewedwith lesser resolution. A map orientation key selects an orientation ofa direction on the map with a direction on the visual display, forexample, orientations of north up or current ground track up. It isnoted that these map functions are generally known, and known techniquesmay be generally applied for such map functions. According to thepresent invention, in addition to normal map functions, the event datamay be overlayed on the map to provide additional dimensions of displaydata. Further, by providing these data, which are dynamic, the mapsystem becomes useful even to travelers who are well aware of thegeography and layout of the region being traveled.

A 900 MHz spread spectrum communications system operates as follows. TheRF receiver includes an antenna, low noise amplifier (LNA) with a noisetemperature below 80 degrees Kelvin and a helical bandpass filter tocancel the image frequency noise. The filtered signal is thendownconverted to an intermediate frequency (IF) of about 70 MHz, whichis the result of mixing the filtered received signal with a localoscillator signal of between about 832-858 MHz at about 17 dbm. Ofcourse, other tuning frequencies may be selected, for example, to avoidinterference with other equipment. The local oscillator thus operates atabout 850 MHz and is locked to a reference of 10.625 MHz. The 70 MHz IFfrequency is amplified and filtered by a SAW filter 906 with a bandwidthof 1.5-10 MHz, depending on the data signal bandwidth. The IF is thendemodulated to baseband, employing a demodulator using an inversesequence from the transmitted spread spectrum sequence. Thus, in afrequency hopping embodiment, the demodulator synthesizes a signalhaving the appropriate frequency sequence. In a direct sequence spreadspectrum embodiment, the demodulator provides the appropriatepseudorandom code sequence to demodulate the received signal. Timesynchronization may be effected by using the timing functions of the GPSreceiver. The demodulated signal is then decoded into messages, whichare typically digital bitstreams.

In a 2.4 GHz system, the RF semiconductor technology will typicallyinclude gallium arsenide integrated circuits. In a 5.8 GHz system, theRF section semiconductors are preferably silicon germanium. Oncedemodulated to below about 1 GHz, standard silicon technologies may beemployed.

The baseband demodulator may also comprise a digital radio, employing adigital signal processor, receiving a digitized IF signal and outputtinga data stream. In this case, it may be preferred to digitize at an IFfrequency below 70 MHz. For example, with a data stream having abandwidth of 1.5 MHz, the preferred IF is 3-10 MHz, with quadraturedigitization of the analog signal at that IF. The IF signal may beprocessed in parallel with a plurality of demodulators, allowingmultiple signals to be received simultaneously.

In the 900 MHz embodiment, a PLL, such as a 1.1 gigahertz PLL frequencysynthesizer, Part No. MC145190 available from Motorola Semiconductors,Phoenix, Ariz., may be used to generate the first IF. This frequencysynthesizer, referenced to the 9.6 megahertz reference frequency,generates a local oscillator signal of approximately 860 megahertz. ThisPLL synthesizer chip produces a locked stable output signal which is lowpass filtered to produce a variable voltage to control voltage controloscillator. VCO is, for example, Part No. MQC505-900 operating atapproximately 860 megahertz and available from Murata of Tokyo, Japan.The feedback through sense keeps synthesizer chip stable to produce astable, fixed course output. A second PLL produces a fine controlfrequency. The second PLL includes a synthesizer chip, e.g., Part No.MC145170 available from Motorola Semiconductor of Phoenix, Ariz. ThisPLL frequency synthesizer chip has digital controls for control by amicrocontroller. The output of the fine synthesizer chip is low passfiltered to produce a variable DC voltage to control a voltagecontrolled oscillator, e.g., Part No. MQC309-964, operating within the900 megahertz band. The fine adjust frequency is band pass filtered withan SAW band pass filter with a center frequency of approximately 38megahertz. The band pass filter is, for example, Part No. SAF38.9MZR80Zalso available from Murata of Tokyo, Japan. The output of the second PLLis controlled in accordance with the output frequency desired based onthe frequency of the hop transmitted at the current time. By adjustingthe fine frequency, which would be mixed with the coarse frequency, theoutput frequency in the 900 megahertz band is produced with very littlephase noise, very little phase jitter and extremely narrow noise skirt.Thus, this double loop system serves to demodulate the signal to a lowIF frequency or to baseband.

There has thus been shown and described novel communications devices andsystems and methods which fulfill all the objects and advantages soughttherefor. Many changes, modifications, variations, combinations,subcombinations and other uses and applications of the subject inventionwill, however, become apparent to those skilled in the art afterconsidering this specification and the accompanying drawings whichdisclose the preferred embodiments thereof. All such changes,modifications, variations and other uses and applications which do notdepart from the spirit and scope of the invention are deemed to becovered by the invention, which is to be limited only by the claimswhich follow.

1. A method for alerting a driver of a driven vehicle about an unsafe traffic condition, the method comprising: detecting, by one or more of a radar detector, a Light Detection and Ranging (LIDAR) detector, or a camera, a braking event of a nearby vehicle; storing, in a storage device, the braking event of the nearby vehicle; communicating a signal indicative of the braking event of the nearby vehicle to a brake system of the driven vehicle; and alerting the driver, by one or more of a user display alert or an audible alert, of the braking event of the nearby vehicle.
 2. The method of claim 1, further comprising: detecting, by the radar detector, the braking event of the nearby vehicle.
 3. The method of claim 1, further comprising: detecting, by the LIDAR detector, the braking event of the nearby vehicle.
 4. The method of claim 1, further comprising: detecting, by the camera, the braking event of the nearby vehicle.
 5. The method of claim 4, further comprising: detecting, by the camera, an illumination of a brake light of the nearby vehicle.
 6. The method of claim 5, further comprising: detecting, by the camera, an illumination of a center brake light that is not normally illuminated; and inferring the braking event of the nearby vehicle based on the illumination.
 7. The method of claim 1, further comprising: detecting, by the one or more of the radar detector, the LIDAR detector, or the camera, deceleration of the nearby vehicle.
 8. The method of claim 7, further comprising: detecting, by the radar detector, the deceleration of the nearby vehicle.
 9. The method of claim 7, further comprising: detecting, by the LIDAR detector, the deceleration of the nearby vehicle.
 10. The method of claim 7, further comprising: detecting, by an optical sensor, the deceleration of the nearby vehicle.
 11. The method of claim 1, wherein the one or more of the radar detector, the LIDAR detector, or the camera is integrated into electronics of the driven vehicle.
 12. The method of claim 1, wherein communicating the signal indicative of the braking event of the nearby vehicle to a brake system of the driven vehicle includes communicating the signal over a digital data bus.
 13. The method of claim 12, wherein the digital data bus is a vetronics data bus, and communicating includes communicating, by the vetronics data bus, the braking event of the nearby vehicle to the brake system of the driven vehicle.
 14. The method of claim 1, further comprising: displaying the user display alert in the form of visual graphic information on a display device; and alerting the driver of the braking event of the nearby vehicle using the visual graphic information displayed on the display device.
 15. The method of claim 1, further comprising: displaying the user display alert in the form of visual alphanumeric information on a display device; and alerting the driver of the braking event of the nearby vehicle using the visual alphanumeric information displayed on the display device.
 16. The method of claim 1, further comprising: alerting the driver of the braking event of the nearby vehicle using one or more indicator lights.
 17. The method of claim 16, wherein the one or more indicator lights include one or more light emitting diodes (LEDs).
 18. The method of claim 1, further comprising: alerting the driver of the braking event of the nearby vehicle using the audible alert.
 19. The method of claim 1, further comprising: generating, by an audio transducer, a spoken-voice alert; and alerting the driver of the braking event of the nearby vehicle by the spoken-voice alert.
 20. The method of claim 1, further comprising: tamper proofing the one or more of the radar detector, the LIDAR detector, or the camera.
 21. The method of claim 1, further comprising: analyzing, by the one or more of the radar detector, the LIDAR detector, or the camera, traffic control indicia; processing, by a processor, the braking event and the traffic control indicia; and determining a priority of events stored in the storage device dependent on the traffic control indicia.
 22. The method of claim 21, wherein the traffic control indicia includes at least one of a speed limit, a caution, or a traffic light.
 23. The method of claim 1, further comprising: braking the driven vehicle in response to the signal indicative of the braking event of the nearby vehicle.
 24. A system for alerting a driver of a driven vehicle about an unsafe traffic condition, the system comprising: one or more of a radar detector, a Light Detection and Ranging (LIDAR) detector, or a camera configured to detect a braking event of a nearby vehicle; a storage device coupled to the one or more of the radar detector, the LIDAR detector, or the camera, and configured to store the braking event of the nearby vehicle; a digital data bus coupled to the one or more of the radar detector, the LIDAR detector, or the camera, and configured to communicate the braking event of the nearby vehicle to a brake system of the driven vehicle; and one or more of a user display alert or an audible alert configured to alert the driver of the braking event of the nearby vehicle.
 25. The system of claim 24, wherein the radar detector is configured to detect the braking event of the nearby vehicle.
 26. The system of claim 24, wherein the LIDAR detector is configured to detect the braking event of the nearby vehicle.
 27. The system of claim 24, wherein the camera is configured to detect the braking event of the nearby vehicle.
 28. The system of claim 27, wherein the camera is configured to detect an illumination of a brake light of the nearby vehicle.
 29. The system of claim 27, wherein the camera is configured to detect an illumination of a center brake light that is not normally illuminated, and the camera is configured to infer the braking event of the nearby vehicle based on the illumination.
 30. The system of claim 24, wherein the one or more of the radar detector, the LIDAR detector, or the camera is configured to detect deceleration of the nearby vehicle.
 31. The system of claim 30, wherein the radar detector is configured to detect the deceleration of the nearby vehicle.
 32. The system of claim 30, wherein the LIDAR detector is configured to detect the deceleration of the nearby vehicle.
 33. The system of claim 30, further comprising an optical sensor, wherein the optical sensor is configured to detect the deceleration of the nearby vehicle.
 34. The system of claim 24, wherein the one or more of the radar detector, the LIDAR detector, or the camera is integrated into electronics of the driven vehicle.
 35. The system of claim 24, wherein the digital data bus is a vetronics data bus, and the vetronics data bus is configured to communicate the braking event of the nearby vehicle to the brake system of the driven vehicle.
 36. The system of claim 24, further comprising a display device, wherein the display device is configured to display the user display alert in the form of visual graphic information, and the display device is configured to alert the driver of the braking event of the nearby vehicle using the visual graphic information displayed on the display device.
 37. The system of claim 24, further comprising a display device, wherein the display device is configured to display the user display alert in the form of visual alphanumeric information, and the display device is configured to alert the driver of the braking event of the nearby vehicle using the visual alphanumeric information displayed on the display device.
 38. The system of claim 24, further comprising one or more indicator lights, wherein the one or more indicator lights are configured to alert the driver of the braking event of the nearby vehicle.
 39. The system of claim 38, wherein the one or more indicator lights include one or more light emitting diodes (LEDs).
 40. The system of claim 24, wherein the audible alert is configured to alert the driver of the braking event of the nearby vehicle.
 41. The system of claim 24, further comprising an audio transducer, wherein the audio transducer is configured to generate a spoken-voice alert and to alert the driver of the braking event of the nearby vehicle by the spoken-voice alert.
 42. The system of claim 24, wherein the one or more of the radar detector, the LIDAR detector, or the camera is tamper proof
 43. The system of claim 24, further comprising a processor, wherein: the one or more of the radar detector, the LIDAR detector, or the camera is configured to analyze traffic control indicia; the processor is configured to process the braking event and the traffic control indicia; and the processor is configured to determine a priority of events stored in the storage device dependent on the traffic control indicia.
 44. The system of claim 43, wherein the traffic control indicia includes at least one of a speed limit, a caution, or a traffic light.
 45. The system of claim 24, further comprising: the brake system of the driven vehicle.
 46. The system of claim 45, wherein the brake system of the driven vehicle is an antilock brake system.
 47. The system of claim 24, further comprising: the driven vehicle.
 48. A system for alerting a driver of a driven vehicle about an unsafe traffic condition, the system comprising: means for detecting a braking event of a nearby vehicle; means for storing data indicative of the braking event of the nearby vehicle; means for communicating a signal indicative of the braking event of the nearby vehicle to a brake system of the driven vehicle; and means for alerting the driver of the braking event of the nearby vehicle. 